Testing your modem connection
Follow these steps to test whether you can send commands
to your modem:
Log in as root.
Add a ``Direct'' line entry for your modem to the
/usr/lib/uucp/Devices file if one does not
already exist. You can specify either the modem or
the non-modem control device for the
port to which the modem is attached.
For example, the following Devices entry is for
a modem connected to a single port on COM1:
Direct tty1A - 9600 direct
Establish a direct connection to the modem so that you can
send commands to it.
This connection uses the ``Direct'' line in the Devices file.
For example, if the modem is connected to a single port on COM1,
enter the following command:
cu -ltty1A dir
You should see a message
OK (AT-compatible modems)
0 to indicate that the modem is ready to accept commands.
If you see the message
cu: dir permission denied,
you do not have write permission on the
Set the correct ownership and permissions using the commands:
chown uucp:uucp /usr/lib/uucp/Devices
chmod 644 /usr/lib/uucp/Devices
If you do not see a message indicating that the modem is
ready to accept commands:
Check that you entered the cu command correctly.
Ensure the ``Direct'' entry in the Devices
file is correct.
Use the hwconfig command to check that the serial
port is configured.
Use the l command to check
that the device files associated with the port
(such as /dev/tty1a and /dev/tty1A) have
owner and group both set to uucp. If not, change these
using the commands:
chown uucp:uucp /dev/tty1a
chown uucp:uucp /dev/tty1A
The instructions that follow assume an AT-compatible
command set and response codes. Other modems may use other
conventions. Consult your modem documentation for further
details. The instructions are illustrated by
``Testing a modem connection''.
Testing a modem connection
If you see a message from the modem indicating that it is ready to accept
commands, enter AT.
An AT-compatible modem should return
If you have set the modem to
return numeric result codes rather than text,
If you do see
OK, your modem is ready to dial out.
Check that the ``Send Data'' light
on the modem flashes when you press a key.
This indicates the modem is receiving signals from the computer.
If this light is not flashing, check your cable and modem switch settings.
If the ``Send Data'' light flashes, but you still do not get an
OK response from the modem, enable the modem's echo
capability and responses to commands by entering
If your terminal still does not display
connect the modem to another port (COM1 or COM2).
If the modem works with the new port, check that
the device is using the correct interrupt vector.
(Serial port COM1 uses interrupt 4;
COM2 uses interrupt 3.)
If the terminal does not echo the
when it is connected to the new port,
check your cable again. You can also connect a
terminal to the port (with a proper terminal cable)
and verify that the port works. If the modem returns
garbage, then try connecting at different speeds; some
modems can be set to communicate at the DTE connect
speed, while others communicate at a fixed speed.
If the modem still does not respond properly, the
modem may be defective.
Testing whether you can dial out
Configuring remote connections
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003