HP EISA/PCI Multiplexer Family Cabling, Diagnostics and Troubleshooting Manual

Troubleshooting and Diagnostics

Troubleshooting

• The port and printer are mismatched on baud rate, character size or

parity

• Printer losing stty settings after closing port

Tests:

1. Use

emux_diag

Diagnostics to send data to the printer. Verify that

cables and connectors are attached firmly and the printer is powered

on and placed on-line.

2. If no data prints in step 1 above, check the port by placing a terminal

in place of the printer and use

emux_diag

Diagnostics to send data. If

the terminal works, and the printer doesn’t, check your printer

documentation to see if the printer requires any special handshaking.

If this is the case, your printer may require a special cable. If neither

device works, the problem may lie with the port. Make sure that

you’re using the correct device name. Try the printer on another port

that you’ve verified works.

3. If your printer is overflowing, the port may be losing its stty settings.

This sometimes happens when the print spooler opens and closes the

port between print jobs. To keep the port open and always force

software flow control on the ports, enter these two commands:

emux_stty +lp < /dev/tty1a1

emux_stty + ixon < /dev/tty1a1

4. If you still have an overflow problem, lower the baud rate to a low

baud rate such as 300 baud. If the overflow doesn’t happen at 300

baud, you have a handshaking problem. Check your printer setup or

switches and make sure

XON/XOFF handshaking is setup. Also see

the printer setup section in your HP-UX system administration

manuals.

Modem Connection and Troubleshooting

After successfully installing terminals and printers on your HP-UX

system, you may want to add a modem for communication to other

computers. The following is a step by step quick reference for doing so,

but we suggest that you refer to the HP-UX system administration

manuals for detailed information.

1. Edit the

/usr/lib/uucp/Devices

file. For example, for a Hayes compatible

2400 baud modem (where

1a16

is the port where the modem is

located):