Configuring a Device for a Modem

Use these procedures to configure a Digi serial device for a Dial-in/Dial-out modem connection. Configuring a device for a modem requires familiarity with both the operating system and the modem being used. While the following procedure is sufficient for most cases, it may be necessary to take additional steps to properly configure your modem or to set up the operating system for a specific application.

Procedures

Configuring the UNIX Device

1. Connect a serial cable between the port and modem.
2. Power the modem on.
3. If you are using 8-pin RJ-45 cabling from the Digi serial port to the modem, enable altpin by inserting a ditty command or altpin option to an existing ditty command for the port in the file /dev/rc.d/8/userdef.

   Example

   ditty altpin device

   where device is the name of the Digi device.

   Note: By inserting the command in the startup file, it will execute every time the system is booted. For the altpin option to take effect immediately, enter the ditty altpin command at a SCO Unix prompt.

4. Edit the /etc/inittab file on the SCO Unix server. Change the upper-case device to the letter o by editing the letter or number at the end of the line for the device. See /etc/gettydefs for inittab letter and number definitions.
5. Disable the modem control and non modem control devices for the port by entering:

   disable modem-control-device
disable non-modem-control-device

   where modem-control-device is the name of the modem control device for the port and non-modem-control-device is the name of the non modem control device for the port.

6. Edit the file /usr/lib/uucp/Devices. Add a Direct line for the device like this:

   Direct ttyh1a - 38400 direct device

   The "D" in Direct has to be the first character on the line.

Configuring Modems for Dial-in

1. Comment out any ACU lines relating to this device until dial-in is working properly.

   Some applications may require an ACU entry in the Devices file. If an application requires an entry, refer to the modem manual or to the modem manufacturer for the correct modem initialization string, and to the SCO Administration handbook for guidance on setting up an appropriate ACU entry that uses this initialization string.

2. Connect to the modem. At a root prompt, enter this command

   cu -l /dev/device -s 38400

   where device is the name of the non modem control device for the port.

3. Set the modem to answer after the first ring with this command:

   ats0=1

4. Enter the following command to train the modem to the port speed:

   at&w

5. Enter any other desired modem commands.
6. Disconnect from the modem by entering a tilde-period:

   ~.

7. Configure flow control on the port. Hardware flow control is typical and can be configured by inserting this command at the end of the file /etc/rc.d/8/userdef:

   ditty rtspace ctspace -ixon device

8. To add dial-in capability, enter this command at a root prompt:

   enable device

   In SCO OpenServer, the upper case device name is for dial-in, the lower-case name is for dial-out and modem configuration.