Axis Communications' NPS 550 Ethernet print server adds multiprotocol smarts to any printer
Ben Smith
Today's multicultural networks make sharing peripherals complicated. With various PCs, Macs, and Unix boxes linked through the same cable, a shared printer must understand several LAN protocols in addition to juggling print jobs. Many modern printers understand multiple protocols, though at some extra cost, through their built-in standard or optional network connections.
A more effective and flexible way to make printers available to all systems on a network can be an external multiprotocol print server. These small boxes attach several printers directly to a network, interpreting various LAN protocols and managing job flow. A good one like the Axis NPS 550 Ethernet print server ($695) can also s
implify administration.
While a print server can turn older printers into network printers, it can also be a better buy than a new network printer. That's because printers become technologically obsolete long before print servers do. If you pay more for a multiprotocol network printer, you throw away that extra investment when you replace the printer.
You can move plug-in print-server cards from one printer to another, but only as long as you stick to one printer family. A card designed for a Hewlett-Packard LaserJet II, for example, will not work in a QMS printer. An external print server works with almost any printer and can attach more than one printer to a network.
There are more than just financial advantages to going with an external print server. You get a dedicated processor that can manage print jobs coming from multiple sources and provide higher throughput. With the NPS 550, you also get Axis Communications' virtual printer technology, which vastly simplifies the problems of pr
oviding different printer configurations for different users.
The NPS 550 provides eight virtual printers, each of which is a custom printer configuration that you can select by name. You can, for example, set one virtual printer to use the letterhead tray and another to use the plain-paper tray. To the network user, the virtual printers appear as separate printers, whereas they may actually be the same physical device but with different print-control values.
Axis's automatic ASCII-to-PostScript conversion lets you print ASCII files on PostScript printers. The NPS 550 will detect ASCII files sent to any virtual printer set for this feature and wrap them with PostScript code.
You can connect the NPS 550 Ethernet print server to either thin Ethernet (10Base-2) or twisted-pair Ethernet (10Base-T). The NPS 550 automatically and simultaneously handles TCP/IP, Novell NetWare, Apple EtherTalk, and NetBEUI, and it interfaces with Unix (BSD, System V, and AIX), IBM MCS, MS-DOS, Microsoft Windows,
Novell Portable NetWare, and Apple Mac OS. (The unit I tested did not support NetBEUI; the current product does.) Axis also sells the NPS 530, a pocket print server that supports Novell NetWare and NetBEUI for $399, and these plus TCP/IP and Apple EtherTalk for $599. The NPS 650 is a multiprotocol Token Ring print server that supports Novell NetWare and NetBEUI for $795, and also TCP/IP for $995.
With the NPS 550's two Centronics parallel ports and one nine-pin RS-232 serial port, you can simultaneously drive three printers. I tested the NPS 550 with a Dataproducts LZR 965 PostScript printer attached to one parallel port; the capability to wrap PostScript around plain text was invaluable. I hooked an HP LaserJet 4L, a PCL-controlled printer, to the second port.
The parallel ports are rated at above 100 KBps (with burst rates as high as 250 KBps)--more than fast enough to handle two HP LaserJet 4Si MX 600-dpi printers. You can set serial-port transmission as high as 38.4 Kbps and select either XO
N/XOFF (software) or RTS/CTS (hardware) handshaking. As serial printers are almost an extinct species, you'd typically use the serial port to connect to a plotter or specialized display that uses only serial communications. The serial port is on the front of the 8- by 5- by 2-inch NPS 550.
The front panel has four status LEDs to indicate power, network activity, printer activity, and print-server status. Also on the front is a test button. In addition to printing out a simple test page with some basic statistics and operating instructions, you can use the button to print out the entire set of more than 150 parameter settings, plus the 17-page set of installation and integration instructions that reside in ROM--a truly nice feature. Those little network peripherals manuals always seem to be somewhere else when you need them.
Evaluating the NPS 550
I found the NPS 550 easy to install and use in the NetWare, Apple EtherTalk, and most Unix TCP/IP environments. With NetWare 3.11, I only had to run
PCONSOLE to add a print server (the name must include the Axis serial number) and then assign the print server to a NetWare print queue. I had some difficulty making the second port available through NetWare. (The relationships between NetWare print servers, print queues, print jobs, and the utilities to configure them weren't very clear to this Unix-minded reviewer.)
The Mac installation was easy. When I powered up the NPS 550, it advertised its existence to Apple EtherTalk clients. Mac users on the network just needed to select one of the Axis virtual printers from their Chooser menus.
The only complex installation was for the Unix systems. Some of the complexity arose from the fact that Axis provides several different Unix print-spooler interfaces for both System V spoolers and BSD spoolers. Once you use ARP (address resolution protocol) to assign an IP address and name to the print server, you must then decide which program the Unix print spooler will use to communicate with the printer: FT
P (a simple copy without any error logging), a named-pipe daemon, or an Axis-written interface to the printer that sends error messages to the user as E-mail. Systems with BSD's printcap-based print spooler also have the last option.
The source code and installation instructions for all these methods exist in the print server's ROM. You copy the instructions to each of your print-spooler hosts using ftp. The named-pipe daemon, however, requires a compiler for installation on your system. (Even without a Unix print spooler, you can still print by copying your file to the printer with ftp. This is also a way of testing the basic setup.)
You can manage the Axis server from any system that has an ftp utility--even a Macintosh, if you have FTP for your Mac. You can also use menu-based DOS and Windows interfaces provided by Axis, or you can go with an SNMP interface program. The FTP method consists of downloading a configuration file, editing it, and then uploading it to the print server--a method ver
y much in the Unix tradition. Axis has cleverly written the print server's FTP daemon to give you informative error messages when you send improper configuration settings to the print server.
I found the on-line instructions and the 50-page user's manual clear and comprehensive. For an extra $30, you can get an optional technical-reference manual, an excellent work of documentation that not only tells you what to do but provides some of the theory of why you do it and how the system works. This manual is necessary to fully appreciate the value of the print server, and I think Axis should package it free with the hardware.
Operating Parameters
Sitting on a shelf with a few cables plugged in and its LEDs flashing, the NPS 550 seems an unpretentious little box. When, as a network user, you access a printer attached to the NPS 550, you won't even know the print server exists; its operation is so transparent as to be invisible. When you access the NPS 550's configuration information as a network a
dministrator, however, you will be duly impressed.
From top to bottom of each protocol stack, the NPS 550 is an example of fine engineering and attention to detail. The more than 150 operating parameters that you can modify are a clear symbol of its design quality. For example, you can set the Centronics parallel-port interface timing to three settings: slow (25 KBps), for older printers that don't support standard Centronics timing; standard (the default), up to 90 KBps; and fast (up to 125 KBps), for printers like the HP LaserJet 4Si MX.
You can also specify an action when a job arrives for a printer that's already busy; for example, have a secondary printer handle the job. There are parameters that hold the logical printer names that will be advertised on Macintosh printer Chooser lists. Also, there are parameters that you can use to optionally map NetWare print queues to logical printers within the NPS 550 rather than on the NetWare server.
The largest collection of parameters is dedi
cated to defining each virtual printer. They define the physical printer that a virtual printer represents, the control strings sent to the printer before and after a print job, string and byte substitutions for the incoming data string, whether to enable text-to-PostScript conversion, actions taken when a virtual printer gets a Printer Busy signal from the physical device, and even a flag for a hex dump mode.
Other parameters describe the PostScript that is wrapped around text when that feature is enabled: character font and size, page size and orientation, margins, and line spacing. A virtual printer can even map one of seven 7-bit ASCII character sets (ISO 8859-2, UK English, German, French, Norwegian/Danish, Swedish, and DEC) to the 8-bit IBM PC Set 2.
Not only is the NPS 550 an efficient way to connect printers to Ethernet, it is also a versatile "black box" that you can put between your applications and your printer. As such, the NPS 550 print server is a valuable addition to any Ethernet
LAN that needs shared printers.
The Facts
NPS 550 Ethernet print server $695
Axis Communications, Inc.
99 Rosewood Dr., Suite 170
Danvers, MA 01923
(800) 444-2947
(508) 777-7957
fax: (508) 777-9905
Photograph: With one serial port on the front and two parallel ports on the back, the Axis NPS 550 can connect three printers to a 10Base-2 or 10Base-T Ethernet LAN.
Ben Smith is a testing editor for the BYTE Lab. You can reach him on the Internet at
ben@bytepb
.byte.com or on BIX as "bensmith."
Multiprotocol Print Server
