Preface: I began using these tiny network devices back when I was managing a network of Windows 98 machines almost a decade ago. Over the years they have become more standardized and easier to use, and they can be extremely convenient in home or small office installations. It surprises me that they aren't more popular--I find myself frequently having to explain what these things are and what they can do. Rather than constantly repeating myself, I have posted this webpage so I can refer readers here instead.
These are tiny one-port mini print server devices. A print server is a dedicated device or network computer to which you can connect one or more printers. Local area networks (LANs) are becoming more popular in homes and small offices, and the need arises to be able to share printers with other computers on the LAN. Rather than connecting a printer directly to your computer, you can connect the printer to a print server, with the print server connected to your LAN. All computers on your LAN can then print to the printer.
In large office networks, a print server is often a complete computer in itself, with a monitor, keyboard, and running Windows or linux. Often multiple printers will be directly connected to this computer. In this situation the computer is not meant for general use, but dedicated to the task of feeding print jobs from other computers to the printers.
In a private home or SOHO (small office/home office) environment, a computer dedicated solely to handling printers is overkill. A dedicated print server computer may be appropriate to handle print jobs from several dozen users, but a home/SOHO network will typically have only around 2-10 computers. The need still exists, though, to be able to conveniently share printers, and that's where these devices fit in. They are stripped-down, light-duty devices meant to serve one printer, and are ideally suited to a home or SOHO setting. The smallest of these can be carried in a shirt pocket--which gives rise to the colloquial reference to this class of products as "pocket" print servers.
This photo shows two examples of pocket print servers--here, from D-Link and Hawking Technology. These are both parallel-port print servers. One side of the unit has an embedded 36-pin Centronics plug, while the opposite side has a RJ-45 ethernet jack, a coaxial jack for DC power, and a few status LEDs. There are no fans or moving parts. These unit plug directly into your printer, effectively turning your printer's Centronics port into a network port.
The power supply for each unit is not shown. Like many other portable consumer electronics products, the power supply is a small, sealed transformer block that plugs directly into a 120-VAC outlet.
In addition to the parallel-port/wired units shown here, there are similar products
for USB printers and wireless network connections.
Why Would I Want One?
If you only have one computer, you will connect your printer directly to the computer. If you have more than one computer, though, it would be nice to be able to share the printer. The most straightforward way is to use the "file and printer sharing" facility built into Windows. The printer is directly connected to one computer, and then Windows on that computer is configured to share the printer with other network users. In essence, the computer is doing double-duty, being both a print server while also being a general-use computer.
That works fine if that computer is your main computer, if it will always (or frequently) be powered on, and if the printer is in close proximity to the computer.
The drawbacks are that the computer to which the printer is tethered must be powered on for other computers to be able to use the printer, and the placement of the printer is limited by the size and length of the printer cable. Printers with Centronics parallel ports are the most restricted because their cables are relatively thick, and cable lengths are (or should be) limited to 12 feet. IEEE-1284 (25-pin D-sub) parallel and USB connections are less restrictive. Even so, it may still be inconvenient if you want to place the printer on the other side of the room. Printer cables running across the floor or crossing in front of a doorway can be a trip hazard.
A print server solves the problem of having to leave the main computer on. Relieved of print serving responsibilities, the main computer can be turned off when it is not in use.
Some people opt for home routers or network switches that have a built-in print server. These solve the problem of having to leave computers on, but might still restrict where you can locate your printer. Sometimes the best place for your router (especially a wireless model) may not be near the best place for the printer.
Some people with multiple printers may choose to use a multi-port print server. These may work fine if your printers are near each other, but troublesome if you want the printers in different parts of the building. In addition, these standalone devices need a place to sit, so you'll need to provide a tabletop or desk space on which to place the unit.
Examples of Pocket Print Servers in Use
This photo shows a D-Link DP-101P+ directly attached to the parallel port of a HP Laserjet 4V printer. This is in an office area shared by five employee workstations, where none of the workstations is used as a "main" computer. (Meaning: any of the computers might be turned off at any given time.)
(Yes, the sharp-eyed observer may note the Jetdirect network adapter installed in this 12-year old Laserjet. That card ceased working somewhere along the way, and it was easier to plug in the D-Link rather than replace the Jetdirect.)
The HP Laserjet 2200 has a parallel port buried inside a side cover. This photo shows a Hawking HPS1P connected directly to the parallel port. The power cable and ethernet cable are fed through the cable guide and out the back. The small size of the Hawking unit managed to fit inside the recess, whereas other products (such as the D-Link) would not.
Probably due to its compact size, the Hawking tends to operate hotter than other products. To prevent overheating, the printer's side cover is left permanently detached.
Here is another Laserjet 2200, standing alone along an open wall. This printer is conveniently located near a group of desks for sales agents. The agents use laptops, and it would have been extremely unsightly to stick a desktop computer out in the middle of the room just to provide the agents with a nearby printer.
The brown baseboard along the wall is a wire mold--a steel channel carrying power, telephone, and ethernet cabling to outlets spaced around the room. Behind the leg of the printer stand can be seen a dark brown plate with power outlets and a white plate with phone and ethernet jacks.
Here is another view of the printer in the above photo. The Laserjet 2200 has both a parallel port and a USB port, and this time the USB port was used. Unlike the first LJ-2200 above, this printer was to be standing out in the open, so leaving the side cover off would have been unattractive. Instead, the side cover was left on and a D-Link DP301U was used and stuck to the underside of the printer table with velcro.
This view shows the three wires going into the print server: a black power cable, a white USB cable to the printer, and a blue ethernet cable dropping down to the ethernet jack on the wall.
This HP Laserjet 4L is on a small nightstand and placed in a common area shared by four college roommates. The parallel port is buried under a side cover, which is removed in this photo.
This house has no network cabling into any of the rooms. Instead, the students' computers connect wirelessly to a broadband router placed on a pantry shelf. A D-Link DP311P was chosen and connects wirelessly to the LAN. The print server is shown here attached directly to the parallel port, with its antenna poking out the back.
The printer can be situated anywhere in the house--all that is needed is a pair of power outlets for the printer and print server.
Installing the Print Server
Other than configuring the print server, installation is quite straightforward. Simply connect the device between your LAN and printer, and plug in the power. The illustration below shows a wired print server connected to a typical home LAN. Note that the wireless laptops communicate with the print server through the router's switch, so they can print to the printer even though the print server is not a wireless model.
A wireless print server can be used in situations where it would be difficult or inconvenient to run an ethernet cable back to the router. The next illustration shows such a layout. It is important to understand that in this configuration, the print server is connecting to the router, just as are the wireless laptops. The laptops are not connecting directly to the print server via an ad hoc connection. In this way, anything which is connecting to the router--both wired and wireless computers--can print to the printer.
Configuring the Print Server
This is the trickiest part, and is probably what has given these devices a reputation for being difficult to use. If you're using a network of NT-based computers, I recommend you just follow two simple rules: do not use the manufacturer's software, and set the print server to use a static IP address. With that, you're ready to add the printer to Windows.
Okay, I can sense that you're skeptical. Then read this section for further details.
Add the Printer to Windows
Once you know the IP address the print server is using, you're ready to add the printer to Windows. This involves two separate procedures: add the TCP/IP printer port to Windows, and add the printer, telling it to use that port.
This section provides step-by-step instructions for both processes.
That's it. You can now print to the printer attached to the print server. Note that you'll need to add both the port and printer to any other computers you wish to be able to use the printer, but that's far easier than swapping cables back and forth and installing the print server manufacturer's proprietary software on every computer.