NetWare 4.1/9000 Print Services

B-18
Cabling Printers
Preparing Serial Cables
on pins, and so on).
• A DSR/DTR (hardware handshaking) cable is essentially the same as XOn/XOff
cable, but also requires the DSR and DTR pins (usually pins 6 and 20 on a DB25).
These signals must be crossed in a null modem configuration.
• Hewlett-Packard’s PSERVER and NPRINTER programs query the status of pin
5. However, if you are printing directly, you will be using DOS, which generally
queries pin 6. In order to use both of these pins, their signals must be “pulled
high” (the voltage must be up for both pins). To pull these pins’ signal high, we
strongly recommend you tie pins 4-5-6-8 together at the printer end (but not the
PC end). If you do not tie these pins together, you may find the printer
mysteriously going off-line on the PSERVER console.
• If a cable that you purchase has additional live pins, find out what they are by
using an Ohm meter or similar device. If none of the additional pins are using the
pins mentioned above (ground, CTS, RTS, DSR, and DTR), then there is a good
chance the cable will work. However, the only sure way to find out if a cable
works is to test it in the actual configuration. A serial-diagnostic device, such as
a breakout box, can be useful if you will be working with serial cables frequently.