Configuring HP-UX For Peripherals

132 Chapter4

Conﬁguring Terminals and Modems

Troubleshooting Terminal Problems

/dev/tty is a pseudo-device used in many places to refer to the login

terminal.

Step 12. Check the functionality of your hardware.

a. If the unresponsive terminal has a self-test feature, activate it. If not,

power the terminal off, wait several seconds, and power the terminal

back on.

b. Swap the unresponsive terminal with one known to be functioning.

Swap only the terminal and keyboard. Attach the properly

functioning terminal to the same cable the unresponsive terminal

used. Plug the unresponsive terminal and keyboard to the same cable

used by the properly functioning terminal and see if it works there.

If the properly functioning terminal does not work on the

unresponsive terminal's cable and the unresponsive terminal works

at the new location, the unresponsive terminal is not the problem.

c. Check the cable connecting the unresponsive terminal to the

computer. Swap the suspect cable with a known good one. If this

solves the problem, the cable is bad or is not wired correctly. If this

does not solve the problem, your MUX, port, or interface card might

be malfunctioning.

d. On Series 800 multiplexers, problems occur when

• /dev/mux

is deleted or has inappropriate permissions.

• the download ﬁrmware is deleted or has inappropriate

permissions.

• /sbin/dasetup is not run from /etc/inittab. dasetup should

only be run from inittab. Do not run it in any state other than

single-user mode.

Garbage Displayed on the Terminal Screen

If garbage is mixed with valid data, the problem might be:

• Noise on the data line, because

— RS-232-C cable is too long (maximum recommended length is 50

feet or 15 meters at 9600 baud).

— data cable is situated near electrically noisy equipment, such as

motors.