Note. The article is published with changes. Last revision dated 06/25/2007.

What does the average user know about print servers? “These are things that allow you to connect a printer to a local network so that you can print from multiple computers.” Actually, it was not necessary to know anything more in the old days, because historically it so happened that print servers were expensive accessories for expensive office printers, system administrators were engaged in their purchase and maintenance. Now you will not surprise anyone with a home printer, and network equipment manufacturers are vying with each other to tempt consumers with the possibility of wireless printing at an affordable price: from $ 50 for a stand-alone device or almost the same for a network combine (Internet gateway with a built-in print server). From the wealth of proposals, eyes run wide, and it is difficult to understand how one model differs from another.

After receiving the task to clarify the situation, it did not take long for your obedient servant to put himself in the place of the reader and decide at what level to start the explanation, since his own knowledge in this area did not differ much from that given in the previous paragraph - and this despite the experience in operating and setting up quite expensive models of network printers. Gradually it became clear that there was nothing surprising in that, because the more functional the printer and the server, the easier it is to make them friends with each other. When it comes to the budget segment, problems specific only to it appear. Unfortunately, the cause of the main problem - the compatibility problem, which will be discussed below - could not be clearly determined. A technical specialist with experience working in the Russian representative offices of two well-known printer manufacturers commented on the situation as follows: “As a rule, for a printer manufacturer, these devices are just one of the accessories, which are not very popular and not promoted a priori. Due to the fact that compatibility information is usually not needed by anyone, it is not easy to get to the bottom of it even for a company employee. Therefore, the article presents personal observations of the test group of printers and servers, as well as information from open sources.

The concept of "plug and play" in relation to IP networks is still more science fiction than reality. Therefore, for competent work, deep knowledge is required, which most consumers do not have. And since the print server may be the first network device to make you think about the mechanisms of networking, at the beginning of the article there is a short course on network printing technologies and a glossary of key terms from this area - so that device specifications become an open book for you. Well, at least a little more open than for most of the "specialists" involved in compiling these same specifications.

Printer selection

Looking at the scheme of printing processes given in the previous chapter, it is easy to guess that all further conversation will revolve around its lower levels. Let's start from the very bottom - from the printer, because it is he who determines whether it is possible to connect it at all through a print server, and if so, what are the mandatory requirements for the latter.

Before choosing a print server, you need to think carefully about which printer you are going to connect it to: a regular printer or one with a special internal slot for installing the server. We note right away that printers with internal print server or with the ability to install it are the only guaranteed way to achieve the goal. Range external print servers much more diverse, but there are more problems with them; this is what the rest of this chapter is about.

Although this is obvious to many users, we recall that when choosing an external print server, the interface types must first match - LPT or USB. Moreover, the most exact match is desirable: if the printer has a USB 2.0 port, then the server is better with the same port, and not USB 1.1. Some server models have more than one port, sometimes different types, sometimes the same.

Next comes one of the most difficult steps: you need to determine if your printer can even connect through a print server? Manufacturers of both types of equipment try not to advertise the fact that many cheap printers are either not able to work without a computer at all, or require special servers, the cost of which is comparable to an inexpensive PC (due to low demand, they are produced in limited quantities). The reason for this is the small amount of permanent memory of the printer, where only a small loader can fit. This loader is only capable of taking the main part of the program from the computer. Accordingly, the control device, be it a computer or a print server, must have a driver that downloads the necessary program to the printer every time it is turned on. The vast majority of print servers, with the exception of the aforementioned expensive dedicated models, do not offer this feature. It can, however, be obtained using unofficial firmware for some network harvesters. But, firstly, the use of such firmware deprives the user of the company's warranty. Secondly, he first needs to be able to find the necessary files among the many modules that make up the printer driver kit, and fit them either in the internal non-volatile memory of the print server or network combine, or on an external USB key fob, if external drives are supported. Thirdly, the user is required to have a solid knowledge of the Linux system (under which most devices operate) in order to independently write a script that downloads files at the right time and in the right sequence - specifically for their printer model. If this is not a problem for you, examples can be found on the support forum for unofficial firmware for Asus network devices - WL500G.Info.

Since the amount of permanent memory in printers is never specified in public specifications, there is no way to recognize a printer as "oversimplified" based on a suspiciously small amount of ROM. Therefore, many alternative methods have been devised to distinguish a “normal” printer from a “defective” one, but all of them are based on indirect signs and are completely unreliable. Even if the buyer has the opportunity to look inside the printer, there is not always a chance to see the Flash memory chip there, because recently RISC processors with impressive built-in memory are becoming more common. And if the characteristics of universal processors of the ARM family are usually widely known, then specialized microcircuits (ASICs) developed for a specific line of printers are shrouded in trade secrets with seven seals. In any case, knowing the amount of ROM is not enough - this knowledge is useless if the required size for placing the firmware is unknown, because printers vary greatly in functionality - below you will read just that the largest number of supported print protocols in our review was demonstrated by the print server with the smallest ROM.

However, you need to navigate somehow, so consider some indirect signs:

• If the printer hardware supports languages ​​such as PCL, PostScript, Prescribe, etc., with a high degree of probability we can say that there will be no problems.
• If the specification contains words like GDI, host-based printing or Windows printing, there is cause for excitement, but it’s too early to despair: in our testing, one such typical budget host-based printer with support for the simplified Samsung Printing Language printed without problems through all tested servers, and for Canon Advanced Printing Technology systems, it is possible to use a specially designed server, albeit quite expensive: about $ 250 for the Axis 1610 model.
• LPT and COM ports, as already mentioned, are usually served by the standard port monitor, so they should not require special treatment. Cases have been reported where a printer with USB and LPT ports did not want to work with a print server via the USB interface, but was successfully used via LPT.
• A status monitor window that pops up when you print can be a wake-up call. But no more.
• Try printing something to a file (see the previous chapter for a description of the FILE virtual port for how to do this). According to the process diagram, redirecting print to a file has nothing to do with connecting to a printer. If with the printer turned off the program will hang or the created file will be of zero size, it is unlikely that you will be able to print over the network. Apparently this happens when the driver tries to download firmware to the printer on first run, and hangs if it can't communicate with it.

What signs not worth it navigate (debunking myths):

• Many people believe that host-based printers lack their own processor and RAM. In fact, with very, very rare exceptions, looking under the cover of such a printer, you will find both there and then (perhaps in the form of a single highly specialized microcircuit), but this does not mean its “normality”.
• For diagnostic purposes, print servers have a test page output function, which is activated either through the web interface or by a button on the case. The latter may seem especially convenient for testing a “server-printer” pair right in the store, but it also doesn’t say anything. The page can be received, but you will not wait for network printing through this server if the driver definitely wants to communicate with the printer (for example, to request service information from it). Conversely, a printer with a native print language may not understand a test page in, say, PCL, but will print data generated by the correct driver in a language that the printer understands.
• A sure sign of "normality" is DOS support. Only this term is too ambiguous. In everyday life, this is the name for the ability to print in text mode, that is, the presence of built-in monospace fonts. In the official specifications, manufacturers mean something completely different:
  • is it possible to print from pure DOS (which is very problematic if the printer has only a USB port);
  • whether drivers are supplied for the most famous DOS applications;
  • whether the technical support service is solving problems related to printing from DOS.
  So if the printer officially does not support DOS, this does not mean that it really does not fit this criterion.

Let's say you're willing to cut corners to ensure you get a "normal" printer. Here, too, it is difficult to give unequivocal advice. If we are talking about a laser printer, it is enough to focus on hardware support for PCL languages. For inkjet printers, this method is not applicable, because in the amateur class, even expensive models rely heavily on computer resources, but network printing is possible on some cheap ones. The best option would be direct testing or purchase with the possibility of a return (money-back) - you should not trust the opinion of a consultant from a computer store alone. Doubt even the recommendations of the printer manufacturer and its consultants; Below is a case where the compatibility of the printer with one very expensive print server of the same company was officially declared by mistake. Do not take the theses of this article as an absolute truth, because drivers and firmware are constantly being improved, so the possibility cannot be ruled out that by the time you read these lines, some of the information about specific equipment models will no longer correspond to reality.

Other print server specifications

Since the servers of the class under discussion do not process documents, they do not need a powerful processor or fast memory. But the amount of memory matters: a capacious RAM helps to free up the client's computer faster, and the number of functions depends on the firmware memory.

An important role is played by the methods of controlling the device:

• The most common management through the web interface, because it is clear, intuitive and requires the user to have the most primitive skills in the browser. Some of the server models we tested had a nasty habit of rebooting after adjusting each setting - just like in that joke: “You changed the position of the mouse. You must restart your computer for the changes to take effect." Moreover, the restart was initiated by the device itself, immediately after pressing the save settings button.
• The traditional method of management via telnet or the console port is aimed at advanced administrators, so often these interfaces are the only ones that allow fine-tuning; the text interface can take the form of a menu or a command line.
• Very useful for initial configuration is the client program for Windows, which helps to set the IP address of the new device without changing the network settings of the computer; if such a program is not supplied, you must first change the IP address of the computer so that it gets into the same IP network with the default address for the print server, or have a DHCP server on the network.
• Some models support the SNMP protocol, which allows you to manage the device and collect statistics automatically. For home appliances and small office use, this is perhaps superfluous, but technophiles will undoubtedly please. However, “SNMP support” in relation to the participants in our testing is loudly said: they can read a narrow list of data, and change even less.

It is quite natural to want to restrict user access to printing functions, but for some reason this possibility is rare.

Keeping a log of work will not be superfluous. During normal operation, there is no need to look there, but for diagnosing problems, this is the starting point.

Typically, you can configure the communication settings for each printer port: speed for USB and SPP/ECP mode for LPT. It is desirable that the printer also be configured to support the PJL language, since attempts to send PJL commands (for example, polling status commands) to a printer that does not understand them will result in printing these commands on paper.

When connecting a multifunctional device to the print server instead of a printer, it is logical to require that both the scanner and fax can also be used over the network. Apparently, this only requires a server from the same manufacturer as the MFP. The most versatile way to get images from a scanner is to download them via the web administration interface as a normal image from the Internet or send them to a local mail server. Working with the scanner through the usual TWAIN and WIA dialogs just won't work - you need special drivers that support network scanning through your specific server model.

Pay attention to external controls. Button test helps to print the basic settings, which can be useful if the management interfaces are not available (for example, you forgot the IP address assigned to the device). True, this requires a printer that understands the print language, in which the print server creates a test page. Button reset allows you to reset all settings if you forget the administrator password; in the absence of this button, only a service center can probably help, but such a server is protected from unauthorized access by people who have physical access to it.

Using a print server and administering it, let's say, is more difficult than switching TV channels. Therefore, the presence of instructions and a help system is a key moment in mastering the device. Unfortunately, none of the tested models can be given an “excellent” mark for documentation: somewhere the presentation is more detailed, somewhere less, somewhere even in Russian, but nowhere did we find full coverage of the features specific to this type of equipment. For some reason, manufacturers especially did not like the IPP protocol: support is declared, but not a word about how to use it (at least what URL the printer has). The result is that the buyer receives two three-carat diamonds and uses them to cut glass.

Do not be too lazy to go to the manufacturer's website to evaluate technical support:

• types of communication with the support service;
• user forum for experience exchange;
• firmware and documentation archive.

Some manufacturers create emulators of their products that allow you to get an initial idea of ​​​​their web interface even before purchase.

Finally, dimensions. If you plan to take the equipment on trips, it makes sense to focus on compact models, which have a body volume of only 60–80 cm² and a weight of 40–80 g (not counting the power adapter). Among stationary models, there are giants that are 20 times larger and 10 times heavier, but they have several ports for connecting printers, sometimes even a built-in switch for a local network, a convenient location of all indicators and connectors, the possibility of wall mounting and various installation options on table.

Test participants

Before proceeding to the actual testing, it is necessary to get acquainted with the tools of this testing - those printers with which the experiment was conducted. Our test population is diverse enough to provide a general picture, but of course cannot cover all possible variations.

• Epson Stylus C65/C67 ($100). A typical inkjet printer with a USB port. Supports printing in text mode and the corporate language ESC / P, which has become the standard for Epson dot matrix and inkjet printers over the years. For each printer of this model installed in the system, a separate copy of the status monitor is started and wants to monitor the printer. Perhaps for this reason alone, it was not possible to print over the network except through the PRTmate protocol. But how it all started well: this printer was able to print test pages of all print servers.
• HP LaserJet 1020 ($170) or LaserJet 1018 ($140). A typical monochrome laser printer for personal use, from the category of "unsuccessful". Supports only its own language developed by Zenografics. To get started, it requires loading the main control program, so ordinary print servers either “do not see” it at all, or it is periodically either active or turned off. None of the tested print servers was able to provide network printing to this printer, although Windows sharing is still possible.
• HP LaserJet 1022n ($310). Despite the fact that the hardware of this model is actually the same as that of the LaserJet 1020/1018 (with the exception of the built-in network adapter), it maintained smooth, friendly relations with all tested servers. Why do you need an external print server for the initially network model, you ask? The answer is simple: you can choose an external server to suit your needs, including wireless connectivity. In addition, there is a modification without a built-in server - just the network model was brought to our laboratory.
• HP LaserJet 3030 ($550). An all-in-one device with LPT and USB ports and hardware support for PCL 6 language. It prints without problems through third-party print servers via any of the interfaces, and with proprietary Jetdirect servers it also scans!
• Kyocera Mita Ecosys FS-1010 ($300). Laser printer for small workgroups. Hardware supports the Prescribe IIe language and its own versions of PostScript II and PCL 6. It also does not create difficulties when connecting to print servers through any of the ports - LPT or USB.
• Samsung ML-1710 ($210). In fact, he was assigned the role of "unsuccessful", because he only has a USB port and his own SPL language, which refers this model to the class of host-based printers. However, in practice it has once again been confirmed that “terrible savage people on the face” upon closer examination may well turn out to be nice guys. The impossibility of printing test pages created by print servers is simply explained: the printer does not understand their language, but this does not prevent it from receiving correctly formed documents from the same print servers, thanks to the driver on the computer.

Inspection results

The tested products were conditionally grouped according to the geographic location of their manufacturers: D-Link and CNet from Asia, HardLink from Europe and Hewlett-Packard from the New World (although, of course, all devices are manufactured in Taiwan and Singapore). The main characteristics are given in the final table, but since they got under the gun servers more attention will be paid to administration issues.

Print Server Specifications

Model	Price 1, USD	Interfaces			RAM/ROM memory, MB	Protocols			Volume 3, cm³ / weight 4, g
		net	Printer	buttons 2		seal	exercise	autoconf.
D-Link DP-301U	65	LAN	USB 1.1	reset	2/0,5	LPR, FTP, ATPS	HTTP, Telnet, RCP, TFTP, SNMP/v1	DHCP	250/118
D-Link DP-G321	145	LAN, 802.11g	2×USB 2.0, LPT	reset	8/2	SMB, IPP, LPR, FTP, ATPS	HTTP, Telnet, RCP, SNMP/v1	DHCP, UPnP	720/325
D-Link DI-824VUP+	130	4×LAN, 802.11g, WAN, RS-232	USB 1.1, LPT	reset	8/1	PRTmate	HTTP, SNMP/v2c	DHCP, UPnP, RIP/v2	1275/525
HardLink HPS-101UW	90	LAN, 802.11g	USB 1.1	reset	16/2	SMB, IPP, LPR, Raw, ATPS, NCP	HTTP, Telnet, RCP, SNMP/v1	DHCP	85/76
HardLink HPS-101U	45	LAN	USB 1.1	No	2/0,5	SMB, IPP, LPR, Raw, POP3, ATPS, NCP	HTTP, RCP, SNMP/v1	DHCP	60/49
CNet CNP101U	70	LAN	USB 1.1	reset	2/1	IPP, LPR, Raw, ATPS, NCP	HTTP, Telnet, RCP, SNMP/v1	DHCP	65/42
HP Jetdirect ew2400	290	LAN, 802.11g	USB 2.0	test	16/4	LPR, Raw, FTP, ATPS	HTTP/S, Telnet, SNMP/v2c	DHCP, SLP, mDNS	435/161
HP Jetdirect en3700	285	LAN	USB 2.0	test	16/4	IPP, LPR, Raw, FTP, ATPS	HTTP/S, Telnet, SNMP/v3	DHCP, SLP, mDNS	435/140

Notes:

1 Price as of November 2005

2 Key symbols: reset- resetting settings to default values ​​(and not rebooting the device at all; it would be more correct to call this button Zap), test- send a test page to the printer.

3 The volume is indicated without taking into account the external antenna.

4 Weight includes external antenna.

D-Link Express EtherNetwork DP-301U

D-Link is known primarily as a manufacturer of "popular" equipment that combines good functionality with attractive prices. Print servers, however, do not look like budget saving champions against the background of competitors. A possible reason is that D-Link is not a direct manufacturer of them, but uses ODM products from Cellvision Systems, a little-known end-customer company (thus, due to the wide coverage of consumers and the resulting feedback, developers are constantly improving the quality of products).

D-Link products (from top to bottom): DP-301U, DP-G321, DI-824VUP+

Installation and initial setup are very easy thanks to the proprietary remote management utility PS Admin. It automatically discovers all compatible print servers on your network and gives you control over their configuration through a common Windows GUI - no need to open a web browser or text terminal, no need to temporarily change the IP address on the network card.

The gentleman's set of printing protocols consists of LPR and AppleTalk, as well as FTP. Compatibility with printers is standard: all of the above, except for "difficult cases" like the Epson Stylus C67 and HP Laser-Jet 1020, is a completely predictable situation, therefore, unless otherwise noted, other print servers assume the same results. The diagnostic page requires the printer to support text mode and is available only through the web management interface, that is, there is no special button on the case for it - only a reset button.

The web interface would have received a good mark if it had not distorted the original look, developed by Cellvision, with traditional D-Link graphic labels - in order to squeeze pictures into firmware memory of the same size, they had to sacrifice their quality, as a result of which they turned out to be sloppy , unpleasant to the eye. Management through the terminal is carried out in the form of a simple menu; For some reason, not all functions present in the web interface turned out to be available.

The DP-301U model is the brother of the Cellvision PRS201U, but don't worry if you like experimenting with firmware: using original firmware without adjusting for hardware differences (hardware version) threatens to fail. It is strange that D-Link also does not particularly focus on the existence of several hardware versions.

D-Link AirPlus G DP-G321

If the DP-301U belongs to the entry level, then the DP-G321 is on the opposite side of the lineup - this is the most functional product from the D-Link range. Already by the increased amount of memory, you can guess that the differences are not only in the additional printer ports and the wireless interface, but also in the available printing methods. Here, among other protocols, support for conventional Windows network printing is implemented, and the device behaves almost like a real computer print server, appearing in a network environment and browsing for available network printers. The only difference is that the default shared printer names correspond to the port names, but you can replace them with any other, just like the server name and workgroup.

Of course, the server does not know how to rasterize documents and perform other tasks that Windows allows you to transfer to the server side. Therefore, SMB printing is possible only if the driver issues a completely ready data stream, which is indicated by the use of Raw as the default format in the print handler.

Exactly the same restrictions apply to the IPP protocol. For some reason, the description of working with it is not in the user manual, so you yourself should guess that in the dialog for adding a network printer, you must select the option Connect to a printer on the Internet and give an address like http://dp-g321/usb2.

This print server was the only one that allowed individual user access to the printer (based on MAC addresses). The significant disadvantages of the DP-G321 include weak wireless network protection: WPA is not supported - only WEP with a key length of up to 128 bits.

D-Link AirPlus G+ DI-824VUP+

By its main purpose, it is an Internet gateway with a hardware VPN accelerator, a built-in 4-port switch and a wireless adapter. Moreover, all functions fit in a ROM half as large as that of the DP-G321, and the cost of such a network combine is less. In general, comparing the specifications of stand-alone print servers and combines with the network printing function, it is difficult for an unprepared person to understand why the latter can cost less, despite a wider range of tasks to be solved - in the same way as it is difficult to understand the difference between independent wireless access points and all those or harvesters. But if you take a closer look, you will notice that the specifications of the combines do not reveal any details about the supported printing technologies. Moreover, independent print servers of even the smallest models are characterized by a fairly long list of operating systems that either have standard clients for the implemented protocols, or they are easy to find and install on their own, and for combines, the presence of some “print drivers” in the delivery kit is succinctly indicated. server" for Windows and Mac OS of certain versions. In fact, this means that the combines provide printing only over TCP / IP and only one, non-standard and low-functional printing protocol, and if there are no proprietary drivers for your version of the operating system, the print function will not be available.

The DI-824VUP+ setup looked like this. In the absence of a utility such as PS Admin, I had to temporarily change the network settings on the computer in order to set the network parameters for the combine. Then the program from the supplied disk added a port monitor for the PRTmate protocol to the system. Setting up this monitor is extremely simple: you need to enter the IP address of the print server and select the printer interface - USB or LPT (the latter appears here as DB-25, because the DI-824VUP + parallel interface has a 25-pin data bus connector). The drivers are arranged in such a way that when you try to add another port of the PRTmate type, a dialog for configuring an existing port is called. Thus, although two printers can be connected to the server, only one of them will be used at a time on each client computer.

From the server side, printing is not only not configured in any way, but it is not mentioned at all in the web interface, except on the current status information page.

Despite the seeming limitations, this server was the only one among those tested, through which it was possible to print on the Epson Stylus C67. At the same time, the Epson status monitor complained about the lack of a printer, but its autoload can be easily disabled using registry editing or a system utility. msconfig.

The telnet control server is not provided in the DI series devices. But the FTP server was found out; there is not a word about it in the specification and documentation, but it exists. Neither the anonymous login nor the administrator password are suitable for it, so its purpose remains a mystery. If this is a back door, then for whom, you ask?

Since the DI-824VUP+ is primarily a router, it comes as no surprise that it supports RIP v1/v2 routing protocols, a firewall, and a detailed activity log.

The general conclusion for this class of devices (network combines) is this: if you are an undemanding home user, buying a combine will be the most effective investment, but standalone print servers are better suited for office use.

HardLink HPS-101UW

The next group of devices is marching briskly under the banner of MAS Elektronik, which is known not only for its HardLink and Xoro trademarks, but also for the distribution of CNet, Invensys Powerware, Mustek, Umax and Avision products in Russia. Apparently, due to the lesser popularity of its network equipment (when compared with the same D-Link), the company offers very interesting solutions at significantly lower prices.

Left to right: HardLink HPS-101U, HPS-101UW, CNet CNP101U

The first thing that catches your eye is the tiny size. Even this model, the largest in its group, fits entirely in the palm of your hand with an external antenna and weighs only 76 g. The secret of miniaturization lies in the use of a two-story printed circuit board with closer mounting of elements. Heat is a side effect, especially noticeable on metal contacts, but the interface cables connected to them help to remove heat.

The set of supported printing protocols is one of the most extensive among the review participants, so the server can serve almost any existing client - Windows, Mac OS, Unix/Linux, NetWare.

On the CD you will find three auxiliary programs. The first is for configuring the print server. It seemed to be more convenient than the web interface, which is a bit clumsy. In the left part of the program window there is a list of detected devices, in the right part there are icons of the configuration options available for the selected device, which is very similar to the familiar Windows Control Panel, and in the lower part of the window a log of the performed manipulations is displayed. The main inconvenience is that at each start, you must first wait until the network scan is over in search of compatible servers. For some reason, the wireless adapter setup wizard converts all WEP key characters to lower case, so if you set the password in text form and it contains uppercase letters (a good password should combine both uppercase letters, lowercase letters, and necessarily numbers), you will have to use other means of control. And it’s still unclear why HardLink devices implement a DHCP server, which is also activated by default: if this is not immediately noticed, after a while the corporate network may be disabled.

The second and third programs are used to add new LPR network ports to the system. Their difference from the standard ones lies in the simplified design of the configuration dialog and the ability to choose between transport protocols - TCP / IP or IPX / SPX. It is also proposed to notify the user "of the completion of printing", but in fact it turns out that this means the completion of spooling. Of course, no one forbids using a standard monitor for LPR ports and managing them using standard tools. Probably, according to the developers, it is faster and more convenient to do this with their programs, because the automatic search for network printers using Windows tools is limited only by the resources of the network environment (Lanman), and for LPR everything would have to be configured manually.

HardLink HPS-101U

Judging by the name, you might think that this is just a truncated version of the previous model - without a Wi-Fi adapter. Nothing like this! They even look similar only in general terms, and as for the insides, they do not have a single identical microcircuit. And the software is also different, ranging from the kernel to the application layer services.

Surprisingly, the modest amount of Flash-memory not only did not prevent programmers from making support for all print protocols that are implemented in the HPS-101UW, but also adding the ability to download jobs from a mail server (POP3 printing). In order to send jobs to the mail server as to a regular printer, you will have to install a special program - the SMTP port monitor. Thus, in the face of this device, a little more than a matchbox, we have the most "omnivorous" print server, which at the same time is the cheapest.

However, nothing comes for free, and there are trade-offs here too. It is impossible to compress the firmware to infinity, so I had to sacrifice control via telnet and simplify the web interface as much as possible. The latter consists of a single page where both statistics and settings change; and all this is designed in the style of “My first steps in learning HTML” - only the configuration program (RCP) saves from contemplation of this horror, but for some reason even it cannot rename the LPR queue and the shared resource of the network environment; by the way, they are called differently, unlike other print servers, where these names always match. Another unusual feature is the ability to print a diagnostic page each time the device is started.

For all tested devices, a scan of the transport ports was carried out in order to check the basic capabilities and identify undocumented features, such as the FTP server on the D-Link DI-824VUP +. During probing, the HPS-101U experienced a partial loss of performance: for example, the LPR port was closed until the print server was rebooted (to do this, unplug the device from the socket) - it is possible that the firmware is poorly optimized for high network traffic.

Minimization did not spare the reset button either: at penny prices for electronic components, each button, connector or indicator increases the size and manufacturing cost no worse than any other microcircuit.

CNet CNP101U

The appearance and model name are reminiscent of the HPS-101U, especially since both devices are supplied by the same company. But that's where the similarities end. With good hardware and software design, the CNP101U gave the impression of being a more polished, user-friendly product, but the pure functionality lags behind: no Windows or POP3 printing. But there is extended support for the Novell NetWare directory service - in addition to Bindery, the ability to work with NDS has been added.

The web interface is truly a piece of art; It would seem that it is quite a typical set of settings, but because of the "stylish and ergonomic" design, it is easier and more pleasant to use it. Telnet - the usual menu. The configuration program is called, like D-Link, PSAdmin, and looks more like the corresponding utility for HardLink HPS-101UW: in the upper half of the window - a list of devices, in the bottom - a list of the main properties of the selected device; after each change, a restart of the print server is required.

As in the case of HardLink, the software archive on the support site is rather modest, falling short of the level of D-Link and HP.

HP Jetdirect ew2400

Products Hewlett-Packard in our review occupies a special position. On the one hand, this device bears the name of a printer manufacturer, that is, it claims to have a more complete coverage of the capabilities of at least one brand of printing devices. After all, as the developers of third-party print servers say about compatibility and functionality: “We don't know what's inside the printers; printer manufacturers don't know what's inside our print servers. Therefore, if the print server of company A does not work with the printer of company B, a representative of none of these companies will be able to competently advise you. Accordingly, the second positive side of the ew2400 was technical support on issues related to HP printers: knowledge base, forum, live chat with a specialist, regular offline correspondence (though everything is in English). The third distinguishing feature was the price: it was interesting to figure out how expedient it is to pay twice as much as for any other participant in the review.

HP ew2400 (en3700 looks the same)

The list of printing protocols did not impress - any budget competitor can do this. Compatibility with printers also turned out to be mediocre: its “native” LaserJet 1020 remained out of work (we will return to this interesting point), but we managed to find a common language with the “foreign” Samsung ML-1710. As you can see, no one deliberately puts spokes in the wheels, and compatibility with other people's printers is a well-documented possibility, but, of course, not guaranteed.

Superiority over all rivals lies in additional functions: through ew2400 you can not only print, but also scan over the network. After connecting the LaserJet 3030 MFP, the server web interface has got new buttons - scan to computer and scan to e-mail. A preview is available before scanning, there is a choice of color depth, document dimensions and data format; unfortunately, you can not specify the resolution and crop. The image is either transmitted to a mail server or opened in a web browser as a normal image from the Internet. To the chagrin of fans of alternative browsers, full-fledged work with the scanner is possible only in Internet Explorer. The server also supports scanning and sending faxes directly from the computer, however, the documentation does not say how to enable these functions - you can only find sluggish hints about the need to reinstall the MFP drivers, supposedly then the installer will understand that he is dealing with a network model. It is difficult to understand the logic of HP programmers, but it turned out to be true: you can select the scanner mode - local or network - only at the stage of installing drivers. Moreover, only the installer can detect network devices that do not have an assigned IP address and allows you to configure their network settings. That is, if the automatic installer does not work for you for some reason (which is far from uncommon for HP), then you will only be able to install drivers manually for local devices, and for network devices - for net devices.

The print server management interfaces left the most pleasant impression due to the abundance of settings and competent design. The fact that we have a serious thing in front of us is emphasized by the option to encrypt the web interface (HTTPS), and you choose the minimum acceptable level of protection at your own discretion and either agree to a self-made authentication certificate or upload one issued by a real certification authority. The telnet terminal interface is in the form of a command line, but a menu can be invoked if desired. The SNMP v2 protocol provides access to a much larger amount of information than other devices. For security reasons, you can disable some of the printing and management protocols. All settings changes take effect immediately, without restarting. If a critical error occurs, depending on the settings, the print server will either stop its activity, like other models considered, or automatically reboot so as not to disrupt the work of your office.

HP Jetdirect en3700

The older brother of the previous participant is less interesting for a novice user: for almost the same price we have a device without Wi-Fi, and even with professional functions, the benefits of which are very doubtful. Therefore, it was not originally planned to appear in the review, but then it had to be taken, because, despite the obvious similarity of the main characteristics, the ew2400 model is not officially equivalent to the en3700 model. For example, in response to a contact with technical support about scanning through ew2400, they were refused based on official compatibility lists, and the advice was to switch to en3700. No sooner said than done. Especially since the en3700 was the only print server officially recommended for the LaserJet 1020, and it would be a sin not to give this printer a last chance.

An autopsy showed that the hardware differences from the ew2400 are only cosmetic, with the exception of the wireless adapter, which is simply not here. The software stuffing is also, obviously, almost the same. But since you can only trust experimental verification, I had to spend time testing.

Another small lyrical digression about the initial configuration of HP network devices. If other devices either have a default IP address, which is clearly stated in the documentation, or offer a proprietary configurator that does not use network layer protocols, then in the case of Jetdirect, the task becomes more complicated. Here, either a DHCP server is needed (it’s good that one was found in the D-Link DI-824VUP +), or you will have to run the proprietary network printer installation program for Windows, which, by the way, allows you to specify the desired address for the print server. Otherwise, you won't be able to do anything because you won't know what the print server's IP address is.

Of course, the results of compatibility tests completely coincided with the achievements of ew2400, in connection with which a second request was sent to the support service: they say, I, a poor user, went bankrupt on your advice for another print server, and things are still there - LaserJet 1020 as he was a "ghost", so he remained. The answer exceeded all expectations: “This printer model belongs to the host-based class and therefore is not supported by any Jetdirect server. Please read the specification carefully. Indeed, the specification on the main site has already been corrected, but on other official sites, for example, German, and on the Internet, the old version has been replicated in countless numbers. Note dated 06/25/2007. The German site was also corrected over time, but if you type "LaserJet 1020" en3700 in the search engine, you can be sure that the above case is not a product of the wild imagination of the author of these lines.

This unpleasant mistake was the result of insufficient testing (for example, the printer was considered a complete analogue of another, proven model), or there was an ordinary typo (the site editor put a tick in the wrong place) - the main thing is that even official sources can be inaccurate, and consultants who they are guided, can mislead you. You should not take this case as a stain on the reputation of Hewlett-Packard: for sure, things are no better for others, and the wider the range of products, the more difficult it is to keep track of it - believe the person through whose hands a sea of ​​specifications of all kinds of computer equipment has passed.

And finally, a few words about the additional features of the en3700 that distinguish it from the ew2400. First, the IPP printing protocol is supported. Secondly, it is possible to restrict access based on 802.1x authentication and SNMP v3. Thirdly, a firmware update utility is supplied, which itself detects print servers present on your network, downloads new firmware files and updates devices that need it. In a word, an administrator's dream (and an accountant's nightmare).

conclusions

External print servers allow you to connect conventional printers to a local wired or wireless network that were not designed for network printing, but do allow it. Many budget printer models require a direct connection to a computer and are not compatible with most print servers. The only printers guaranteed to support network printing are printers that already contain

Print server(from English. print server A print server is a device that allows a group of wired and wireless network users to share a printer.

Technology development

In the summer of 1991, Hewlett-Packard introduced JetDirect technology for the first time, allowing the printer to be directly connected to a local area network. Its first representative was the XIO (Extended Input/Output) interface card, which supports the Ethernet standard and various network protocols (TCP/IP, IPX/SPX, AppleTalk and DLC/LLC). Initially, each protocol required its own card, in the course of subsequent development, new types of connectors were added. In 1992, a card with RJ45 and BNC connectors was introduced, and in 1993, the first with parallel port (LPT). This made it possible to connect JetDirect cards to almost any printer, making it a network printer.

The increase in the range of tasks in the field of printed products and the expansion of the range of digital devices led to the creation of NetUSB technology, which is a USB interface emulator over the network. For the first time, NetUSB technology was introduced by TrendNet (2005 - 2007). It was followed by the company D-Link, releasing its solution (SharePort). Using any of these technologies looks like the printer is connected directly to the computer. These technologies allow you to use other devices in a similar way: MFP, scanner, flash cards, card reader, external hard drive, camera or camcorder.

Today, any company producing network equipment is engaged in the release of print servers.

General information

A print server is a LAN-connected device to which one or more printers are connected (the number of connected machines depends on the type of device). There are two types of print servers: internal and external. External print servers, in most cases, work with any device, regardless of the manufacturer's company, while internal print servers work exclusively with printers from the print server manufacturer. But, regardless of the type of print server, it is "transparent" for operating systems and requires only the correct settings for the used network data transfer protocols (TCP / IP , Internet Printing Protocol, Line Printer Daemon Protocol, NetWare, NetBIOS / NetBEUI ).

Basically, print server models differ in the type and number of ports used to connect printing devices, network speed, dimensions, as well as the range of network protocols that it can support and, as a result, the ability to work in a "multi-operational" network (that is, a local network to which PCs with various types of operating systems are connected).

As a rule, a print server comes with software that allows you to configure the device's operation parameters and has advanced diagnostic and configuration tools, as well as allowing you to connect a network printer on a client computer.

All models of print servers support setting parameters via a web interface, which can be accessed by any computer on the local network.

Principle of operation

A print server is a computer or a separate device that manages printing devices on the same network. Depending on the modification, the print server uses either a 10/100BASE-Т Ethernet port to connect to the network, or connects via a wireless communication channel (IEEE 802.11 b/g/n). There are one or more LPT or USB ports for connecting a printer. In order for a print server to function properly, it must be connected to the network and a printer must be connected to it.

The principle of operation of the print server is to collect print requests coming over the network to the printer from different computers, and transfer information to the printer via the USB port. As a result, the printer remains formally connected to one device, although in fact it is on the network.

Andrey Borzenko

Today, printers directly connected to the network have become traditional office equipment. They provide fast printing and easy installation regardless of location, which is so important to network administrators. However, in organizations with a small and medium-sized local area network, the most common option for shared network printing remains a personal printer connected to one of the PCs (Figure 1). The main advantage of this option is economy. However, keep in mind that this method of printing uses the resources of the PC to which the printer is connected, and the performance of the computer is significantly reduced. So with large volumes of network printing, it becomes very difficult to use this PC for its intended purpose. Devoting one computer to network printing alone, as well as purchasing a dedicated network printer, is often not financially justified, especially if the print volumes do not exceed the capabilities of the printer being used. In solving this problem, the so-called print servers, or print servers, are designed to help.

Print servers are small network devices that can be connected to one or more printers (Figure 2). They are of two types: external and internal (Fig. 3). The latter are made in the form of a board and, as a rule, can only be used with certain printing devices. The most noticeable limitation of internal NICs is that a specific printer must support them. And this means that if the printer was manufactured before the advent of such devices, or if the printer is new, but it does not support internal cards, then you will have to use an external network printing device.

Rice. 2. Print server for two printers.

Rice. 3. External and embedded print servers.

In addition, the internal board serves only one printer. External print servers are capable of serving multiple printers at the same time, thus saving on additional ports. When a single device works with many printers, it also reduces configuration needs and required resources. For example, one IP address is enough for each of the printers, while printers with an internal board will each have to allocate a separate address.

Often, internal network cards have restrictions on the number of supported network protocols and their simultaneous support: it happens that the required protocol is not supported or two protocols cannot work simultaneously.

An external print server provides transparent, network printer sharing. Just like a networked computer with a printer connected to it, an external print server has its own network connection, and the printer (or printers) connects directly to the server. In this case, there is no need to spend money on the purchase and maintenance of a relatively expensive PC - instead, an inexpensive, small-sized, easy-to-use device is used.

Benefits of External Print Servers

Print servers are generally recommended for medium to large networks where remote control of printing devices is required. Their use is especially effective in cases where the network has a lot of printers located on different floors and even in different buildings, and it is necessary to provide the administrator with maximum control options, and the user - maximum convenience for working with them.

Saving money

To print from a computer or file server with a printer attached, you need to have that computer or server, and they are quite expensive. Costs increase significantly if many printers that need network access are distributed throughout the office. Even the simplest computer is significantly more expensive than a powerful multi-protocol print server, the latter supporting multiple printers at the same time. In addition, the print server allows you to reduce the time spent on support and service (maintenance of a computer requires significantly more time).

Unloading the main processor

Processing print jobs takes up a lot of CPU time on the computer to which the printer is connected. If the PC is also performing other tasks or sharing files, printing may significantly affect its ability to perform other tasks. Printing performance also leaves a lot to be desired when the computer is running multiple, processor-intensive jobs at the same time.

The reason for the high load on the processor lies in the so-called software character-by-character I / O mechanism. Its essence is that when the server sends a print job to the printer, a processor interrupt is initiated for each character. It does not matter which computer is used - an outdated XT-frame or the fastest machine based on Pentium 4. The requirements for the server increase significantly if it serves several printers.

The print server uses DMA (Direct Memory Access) instead of software character-by-character I/O. In this case, the processor interrupt is triggered only for entire data packets. Thus, the print server not only offloads the computer or file server, making them more efficient in other tasks, but also allows you to achieve faster network printing.

Convenient accommodation

When you connect printers to a computer or file server, you do not have to select a location. And since servers, for example, are usually located in a secure, specially air-conditioned room or closer to the system administrator, they are often inaccessible to most users, who have to make long "walks" to pick up documents sent for printing. Network print servers, on the other hand, allow printers to be placed anywhere on the network, exactly where they are needed most. Due to their small size, these devices can be connected directly to the printer or placed in places where they do not interfere with anyone.

Additional job processing

Often, in a heterogeneous network environment, print jobs created on different operating systems or networks require additional processing before being sent to a particular printer. For example, many print jobs created on UNIX require "carriage returns" to be inserted at the end of lines, otherwise the printer prints the text in a "ladder". Another standard requirement for pre-processing is to print a cover page for each job so that users can find their documents in the printer's output stack. In many cases, the printer needs to be configured differently for different users.

This feature is often provided on print servers using virtual printer technology, allowing significant savings on the purchase of additional printer devices. In this technology, special virtual printers are configured directly on the print server. Users submit their jobs to the virtual printer, and the jobs are pre-processed according to predefined conditions. For example, one virtual printer can be used to insert carriage returns in jobs from computers running UNIX, another to convert ASCII jobs to PostScript for users whose applications do not support this format, a third to prioritize jobs for users who need provide a certain level of security. In addition, all virtual printers can be configured to print a banner page. The advantage of the print server is that all these virtual printers are located on the same server and all users are served by one physical printer.

Management options

It is vital for network administrators to know what is happening on the network. When the server is tasked with printing, it generates messages about the status of print jobs, the number of pages printed, and notifications about printer problems such as unavailable, paper jammed, or missing. These messages are sent directly to the network administrator by e-mail or logged to the system log.

In addition, print servers often support SNMP management, allowing full control over standard SNMP applications such as Hewlett-Packard's OpenView, Sun's SunNet Manager, or Castle Rock's SNMPc.

Print Server Capabilities

Print servers are currently produced by companies such as Axis Communications (http://www.axis.com), Digi International (http://www.digi.com), D-Link Systems (http://www.dlink .com), Hewlett-Packard (http://www.hp.com), Intel (http://www.intel.com), Lantronix (http://www.lantronix.com), Lexmark (http:/ /www.lexmark.com), Microplex Systems (http://www.microplex.com), NetGear (http://www.netgear.com) and others (Fig. 4). In terms of dimensions, these devices are slightly larger than a conventional video cassette. Each has a power supply connector, a 10/100 Mbps RJ-45 Ethernet jack, and multiple printer ports (parallel and serial). Some devices have built-in hubs. Typically, all print servers can work with text printers and PostScript printers at the same time. Most printers on the market are compatible with these servers, but there are some that do not work with them. These are inexpensive printers such as the HP DeskJet 700, 820, or 1000. They use Windows 95/98 to perform most image rasterization functions and only function when connected directly to a PC running one of these operating systems.

Rice. 4. Print server D-Link DP313.

With embedded Web servers, all print servers can be configured using a browser. New devices usually support the IPP (Internet Printing Protocol) protocols. Automatic IP address assignment and intuitive naming of DHCP and WINS/DNS enabled printers makes them easy to install and configure. Each device can perform a test print or display a status printout containing information about its IP address, active protocols, the number of documents in the print queue, the types of printers connected to it, and other information. Some print servers have a special test button that, when pressed, will print out a diagnostic printout with information. In most cases, the print server is able to determine the type of printer connected and the required network protocols. Automatic speed and media detection eliminates the need to configure these settings during installation.

Typically, each print server comes with a CD-ROM containing configuration and management utilities. Because the new print servers are open architecture, they can be updated by downloading new firmware stored in flash memory. This allows print servers to adapt (at least for some time) to ongoing technical changes.

In order for network servers and client PCs to work with the print server, they must be properly configured with new network printer drivers installed on them. There are two main configuration methods, one is to create a virtual local printer port (on a PC or server) using software supplied by the print server manufacturer, and the other is to use the new IPP protocol (if the client OS supports it). Some print servers have special tools that create an installation disk for a new network printer that contains the printer's driver, as well as the print server's IP address and printer password. You can install the printer driver in another way - using the IPP protocol.

Speed ​​up printing

The printer is the bottleneck in almost any printing configuration. Print servers are capable of delivering speeds much faster than a standard computer parallel port and, in most cases, deliver data faster than a typical printer can handle. For example, Microplex print servers are equipped with parallel ports capable of over 200,000 characters per second. A standard computer parallel port transmits approximately 30,000 characters per second.

Here it should be emphasized once again that print servers support most of the known printing devices - from the latest lasers to the oldest dot matrix printers. In addition, any printing languages ​​are supported, such as PostScript, PCL, HP-GL, and others. The print server doesn't care what type of data passes through it. It simply sends data transparently to the connected printer or printers. The only exception is when special data processing is required, such as conversion from ASCII to PostScript. In this case, the print server only looks at the beginning of the data to determine if a conversion is required.

Generally speaking, in order to evaluate the performance of printing, it is necessary to know the "bottlenecks" of this process. For example, when preparing a print job, the word processor spends time converting the document from its own internal format to a printer format such as PCL or PostScript. The conversion process depends on the size of the document and the performance of the word processor when performing this operation; it can be fast or take a fair amount of time. The conversion time is also highly dependent on PC performance. The time it takes to transfer a job from a word processor to the print queue is called paging time. It is determined by factors such as the performance of the application program in moving data to the printer port (or spooling to print), as well as the performance of the network in sending and spooling data for printing. The time that a print job waits in the print queue is called the wait time. It depends on a number of factors, including the number of jobs in front of it, their size, the speed of the server, and how it is used. The print server periodically checks the print queue, if it exists at all, to see if there are jobs to print. If there is such a queue, and the printer is online and ready to receive, then the print server will begin moving the job from the queue to the printer. This process is called de-paging or queuing, and the time it takes to move the entire print job to the printer is called de-paging time. Factors that govern paging time are the rate at which the print server can purge data from the print queue and the rate at which it sends that data to the printer. Another key factor is the speed at which data is received by the printer.

As practice shows, it is the paging time that often has the maximum impact on the network printing system. In a well-organized network printing system, waiting times are usually short, as the print job is often the only one in the queue. In this case, once the word processor has finished paging, the only thing left for it to do is print, which will take depaging time, depending on the print server.

Print servers serve all jobs on an equal basis on a FIFO basis: first in - first out (First In - First Out), i.e. there is no preference for individual computers or networks. Each I/O port usually has its own queue, which is processed independently of other ports' queues. Thus, a print server with four I/O ports (two parallel and two serial) can support four queues, each serving a different printer. The ports support printing simultaneously without the risk of mixing or job loss.

At any given time, the print server stores only a few kilobytes of data per I/O port, and the rest of the data is stored at the job source. There are simply no print servers on the market today that can fully spool print jobs, so the source computer is always involved in spooling jobs. In most cases, this operation is very fast.

Access control

If the print server is not secured, then no matter how many security enhancements are hidden in the network OS, the network administrator has an open system where there is no way to prevent unauthorized users from accessing it. The ability to restrict printer access has significant potential benefits. In particular, unauthorized use of the printing device leads to increased costs for maintenance and consumables. If the printer prints unauthorized jobs, then it is not available for urgent business projects that have tight deadlines. The consequences of poor control over printer usage can be more severe if print servers serve printers that print receipts, invoices, and other accounting documents. In many cases, access control helps to prevent serious negative consequences that unauthorized printing in institutions that work with confidential documents can entail.

In many cases, network administrators organize a centralized print job queue. Users submit jobs to a centralized queue on the file server, which then forwards those jobs to the print server, which in turn forwards the job to the printer. With this discipline, system administrators can centrally manage all user print jobs. This allows you to take advantage of network OS features such as automatically loading a printer driver when connected to a queue, while maintaining the performance and location freedom of print servers.

In some situations, sending print jobs to a centralized queue is either not possible or efficient. An example is a remote office, equipped only with workstations and connected to the headquarters by a slow communication channel. It is often not possible to create a centralized print queue, either because the file servers are overloaded or for other reasons. In situations like this, it makes sense to have workstations print directly to print servers. Print servers support both shared access and direct printing.

Because the network OS security features can restrict access to only the file server's print queue, any computer connected to the network can send a print job directly to the print server without being controlled by the network OS. A reasonable solution in this case is to equip the print server itself with security measures.

One solution to the problem of unauthorized access is the use of Intel password protection technology. This technology complements the security features found in most network operating systems. A security check is performed whenever a user attempts to print directly to a network printer, bypassing network OS security. For example, with the Intel NetportExpress 10 and 10/100 print servers, administrators can set a password to access any connected printer. In a shared print environment, such as when users submit print jobs to a queue on a Windows NT server, the administrator can configure the NT server settings to forward jobs to the print server with a password. The file server is the only computer that needs to know this password. The administrator controls access to the print queue using normal network OS security. It should also be noted that in a situation where workstations print directly to a printer, there is no centralized print job queue on the network and the network OS does not control access to the print server. Anyone can use the printer. This technology overcomes this limitation by replacing the security features of the network OS. Only those users who know the corresponding password can print documents to a specific printer from their workstations. If the workstation specifies an incorrect password, then the print job simply fails, as if the printer were not connected to the network at all. So, if the administrator has three printers connected to the same print server, then any of them (or all at once) can be provided with a unique password. For example, if monochrome laser and color inkjet printers are connected to the print server, then access to the laser printer can be allowed to everyone, and access to the color inkjet printer can be restricted with a password. Printer passwords can be used on UNIX, Linux, Windows NT, Novell, and even AS/400 systems.

Today, for most new devices, you can restrict network access to them and to their individual printer ports. Such a restriction may be required, for example, if the printers contain special paper (various forms, forms, etc.) or if you want to ensure printing only through a file server (running under Linux, NetWare or Windows NT). If the print server is configured to allow access only to the file server, then users will not be able to print bypassing the file server by communicating directly with the print server. Print servers also have the ability to restrict access to their Web interfaces with a password.

Protocol support

In heterogeneous network environments, administrators must support many different print services and protocols. Print servers allow multiple network users to print to the same printer using different network protocols. Thus, this is a great way to reduce the cost of a workplace. Users can use the same printer even if they are on different platforms. Modern print servers typically support TCP/IP, IPX, DLC/LCC, AppleTalk/EtherTalk, NetBIOS/NetBEUI, LAT protocols, so they can be used even in mixed environments. As for printing protocols, they usually include LPD, RSHD, FTPD, direct connection, PSERVER, RPRINTER, LPD, print manager, etc.

With the constant growth of computer networks, the process of managing print in them is noticeably more complicated. Print servers are designed to solve this problem. And the more "smart" they are, the more functions they begin to take on, the easier it will be for the administrator to solve network problems, and users will be able to work much more efficiently. In recent years, there have been fundamental changes in online printing, and in the foreseeable future this process of change is not in sight of an end. Companies are looking for enterprise-scale remote printing solutions, and network administrators are looking for tools that make management easier and more centralized for printing.

Modern print servers can be generally divided into two types according to the way they connect to the network - wired and wireless. However, do not forget that there are still printers that work through the LPT interface, and therefore it is worth adding one more parameter for comparison - by the type of connection directly to the printer itself. At the moment, a lot of routers have the function of print servers, which reduces the number of network devices used. However, today we will see in more detail in the examples how one independent device can differ from another.

TP Link TL-PS110U

This is the simplest representative of this class of network devices. The print server has one USB connector for connecting one printer and one RJ-45 socket to be connected to the local network itself. The device is compatible with most printers currently on the market and has a very simple setup interface that will be clear to almost any user. Compatibility with most modern operating systems will allow you to easily connect the printer to user computers.

TP Link TL-PS310U

Unlike its younger "brother", this print server supports connecting up to four different devices to it using a special docking station. Thus, on the network, you can “share” not only a printer or MFC, but also a scanner, a webcam or various USB drives. Just like the younger model, this print server has one USB connector and one RJ-45 connector. The device is compatible with most modern printers, and therefore is a good choice for use in a home or small office network.

TP Link TL-PS110P

This print server is somewhat of an anachronism, however, it will be indispensable in those networks where printers with an LPT connection are still used. This device is also wired, and has one connector for connecting to a local network using a twisted pair. However, instead of a USB connector, the print server has an LPT port and allows you to connect most printers through a parallel port. Like the previous print servers reviewed, the device has a simple configuration interface and is compatible with most modern operating systems.

TP Link TL-WPS510U

The main difference of this print server is the wireless connection. TP-Link TL-WPS510U connects to a local network using Wi-Fi technology and provides data transfer at speeds up to 150 Mbps. and has all the necessary security features, including 64/128-bit WEP and WPA data encryption modes, which ensures its operation in any networks. The device is compatible with most modern printers that connect using a USB cable. It is worth saying that the use of wireless print servers allows you to install the printer anywhere in the room, while wired print servers are usually located in close proximity to routers, which is not always convenient.

How do I connect a regular printer to be shared on a network? The answer is obvious - with the help of a print server, the choice of which is more than wide on sale. However, a study of a number of stand-alone entry-level print servers, conducted by the author about three years ago, ended in disappointing conclusions. Firstly, it is impossible to use a scanner over the network (separate or as part of a combine), unless you get an expensive print server of the same brand. Secondly, some printer models, including very popular ones, are fundamentally not ready to work without a direct connection to a computer. The reason for this is that the printer's main firmware needs to be loaded each time it is turned on. Thirdly, and this is the saddest thing, it is impossible to say in advance whether the printer is so "incompatible" - it remains only to predict the probability of a successful outcome based on indirect signs. It's good if someone before you conducted a test and shared their experience, but what about new products? Sometimes misinformation takes place: many users complain about incompatibility, when they simply cannot figure out the settings. And vice versa, the manufacturer claims that the printer works together with such and such branded print servers, but when it comes down to it, it turns out that this is just an "unfortunate typo". Although printer manufacturers are to blame for the inability of printers to function without a computer - partly for good intentions, partly because of the desire to rigidly segment the market - those who create print servers have to take the rap to disgruntled users. They had no choice but to learn how to emulate a USB interface over a network. So, first NetUSB technology appeared in TrendNet devices, and then its analogue called SharePort was released by D Link. Using any of these technologies looks like you have connected the printer directly to your computer. And not only a printer - an MFP, a scanner, a flash drive or a card reader, an external hard drive, a camera or a camcorder. However, despite almost two years of history, the word "NetUSB" is still not heard. Why didn't the happy owners of these products trumpet this good news? The fact is that not everything is as rosy as it seems at first. The USB interface implies that the entire bus on which different devices "sit" is controlled by one computer. That is, several devices can be connected to one computer, but several computers can be connected to one device - no, no. But after all, print servers are created just for this, to ensure the sharing of a device between several computers. Alas, this is not possible in NetUSB mode: the computer communicates with peripherals in exclusive mode. Worse, apart from the computer itself, no one on the outside is able to tell whether the channel is currently in use or idle. Until the client itself closes the communication session, the device remains inaccessible to all other users. We will tell you more about the features of using print servers that emulate a direct USB connection using the example of two models D-Link DIR-655 and TrendNet TE100-MP1U.

TrendNet TE100-MP1U print server mounted on a D-Link DIR-655 network combine.

D Link DIR 655

Let's start with a simpler D Link print server. In fact, it is not a print server at all, but a home router (Internet combine) - it is on these products that SharePort technology began to be tested, of which only the DIR 655 model is now available in Russia. The connector initially did not have such a function in it, and the USB port was intended only for importing and exporting Wi Fi settings. Previously purchased devices require a firmware update to version 1.21, but buyers should also make sure that the hardware version is at least A2.

Front and rear panels D-Link DIR-655.

Key Features of D-Link DIR-655 Xtreme N Gigabit Router
Device type	Internet gateway with built-in switch, wireless access point and print server
Interfaces
External network	1 port 1000Base-T (802.3ab, auto-MDI) with RJ-45 connector
Internal network	4 ports 1000Base-T (802.3ab, auto-MDI) with RJ-45 connector
Wireless network	Wi-Fi 802.11n-draft MIMO with b/g/n mixed mode support; three external dipole antennas (2 dBi connectors, SMA-RP connector)
Printer, 3G adapter	One USB 2.0 connector A
Server features
Network protocols	TCP/IP v4
Print protocols	No - shared network printing is not supported
Network USB	SharePort - exclusive access with automatic virtual port activation and manual deactivation; drivers for 32-bit Windows 2000-Vista
plug&play	DHCP Client and Server, UpnP Advertisement
Administration	Web interface, notifications and logging via SMTP and syslog
Other
Conformity	CE, FCC
Power Supply	External; output 12 V, 2 A
Power consumption	Up to 2.5W without connected peripheral
Working conditions	Temperature 0…+50°C during operation, -25…+55°C during storage; humidity 10-90%
Size (WxDxH), mm	193x117x31
Weight, grams	317
Cost, USD	150

On the body of the device there is a rim that prevents the wide USB plug from penetrating deep into the connector. If you try to insert a flash drive, it will seem that there is no contact, but these fears are unnecessary: ​​firstly, the connector is made shallow, and secondly, the foresight of the USB creators made it possible to take into account such inconsistencies. According to an unwritten rule, the integrated printing functions in routers are performed in the most primitive way - you can't even tell from the web management interface that such a possibility exists at all, since there are no settings and access control provided.

That's all the settings related to printing.

As a rule, routers do not use standard protocols such as Raw / LPR, built into Windows and other systems, but self-made protocols such as PRTMate, for which you need to install drivers that are not available for all platforms. Everything is the same here: the SharePort USB network interface driver is offered only for 32-bit versions of Windows. Normal shared access without using SharePort is not supported.

SharePort utility menu in the system tray.

We will not dwell on the software installation process in detail. One piece of advice: do not waste time trying to figure out the utility for automatically configuring your router and accessing the Internet - it's easier and faster to do everything manually. The built-in help system describes each parameter in detail, thus eliminating the need to look into the user manual. By the way, the manual, like the entire control interface, is only in English so far. The first time you run the SharePort utility, remember to activate the router by right-clicking on the icon in the system tray (next to the clock) and ticking the box next to the name and address of the router in the context menu. Otherwise, you will be confused by the message that no devices and print servers were found.

SharePort utility window: to start using the device, you need to connect it and activate it by selecting the Connect item in the context menu.

The operation process is ingeniously simple. Insert the device's cable into the router's USB port, left-click on the SharePort icon and select Connect from the context menu in the window that opens - everything is as if you connected the device directly to the computer. The standard procedure for discovering a new device will start.

Connecting a new device: step by step.

Alternatively, you can select Manage Device instead of Connect. Then you will first be prompted to install peripheral hardware drivers (if you have not already done so), then asked if you need to add a virtual scanner driver to the system, and finally you will be prompted to use the automatic device activation function when printing starts.

Diagnosis of common problems.

Actually, everything is so elementary that there is nothing more to add. We can safely say that the developers coped with the task: you will not notice any difference with a direct connection to a computer. Even if the connected device is a high-speed hard drive, the bandwidth of the built-in gigabit switch more than covers the characteristics of the USB 2.0 interface. A definite advantage over the TrendNet model concerns the power supply of USB devices. With such a simple task as a USB stick, both coped. But when we tried to connect more powerful "pieces of iron" (measuring devices with their own illumination sources), the D Link device withstood each of them, but its rival was able to master only one of the two models. True, there are more complex options, such as flatbed scanners without external power supply - it was not possible to perform such a check for lack of these devices. But we can definitely say that none of the models provides for connecting several peripheral devices to one USB port through a hub - this will require two-port TrendNet print servers.

In general, despite the simple print server, the DIR 655 router has so many functional features that it deserves a separate review. But within the framework of this material, we will not dwell on them.