Technical data

Managing Peripheral Devices
8.7 Managing Modems
Table 8–9 Troubleshooting Communications Problems
Problem Considerations
Modem does not answer Check that the telephone number being called is correct.
Check that the modem has power.
Check that the host system or device has power and is operating.
If possible, directly connect a standard terminal in place of the modem, and
test the operation directly.
Check that the host modem control signals are present, and correctly wired.
Check that the host device is configured correctly for a modem by using a SET
TERMINAL, SET PORT, or other appropriate host command.
Check the wiring. Look for a broken, miswired, or disconnected wire.
Look for a disconnected connector or a broken, missing, or bent connector pin.
Telephone malfunction Using a standard telephone handset, test that voice calls can be established
on the telephone line.
Is static or other interference noticeable on the telephone line?
No modem indicator lights Check the power connection.
Check to see that the modem is turned on.
Check to see that the modem has passed applicable self-tests.
Try swapping the modem for another device.
No response, or garbled
response to typing
Check that the modem status lights indicate received data on the transmit
line, and transmitted data on the receive line. This can point to the miswiring
of the transmitted and received data. You can wire serial cables and adapters
straight-through or with a cross-over.
Check for crossed signals.
Check for incorrect speed detection. Autobaud detection sometimes sets the
speed incorrectly. On lines that are not enabled for autobaud detection, check
that the line is set for the correct speed. On ports that support it, check the
speeds for both the transmitted and the received data.
Make sure that the port has autobaud enabled, and that the port and the
modem are configured for the same data rate.
Check for interference or a disconnection in the wiring.
Check the wiring for any problems.
Check for any adjacent wiring, power, or video signals that might interfere
with the serial communications.
8.8 Managing Printers
To manage printers attached to your system, perform the following tasks:
Task For More Information
Set printer characteristics Section 8.8.1
Spool printers Section 8.8.2.1
Despool printers Section 8.8.2.2
Test spooling of printers Section 8.8.2.3
8–34 Managing Peripheral Devices