Configuring a Device for a Modem

Use this procedure to configure a RealPort 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.

Procedure

  1. Connect a proper cable between the port and modem. 
  2. On the HP-UX server, use vi to enable the new modem entries in the /etc/inittab file for dial-in. Here are examples of two entries for Digi RealPort ports:

    Xx01:23:off:/etc/getty ttya12 H
    Xx02:23:off:/etc/getty ttyb02 H
  3. Change the word off to respawn for each port you want enabled. For example:

    Xx01:23:respawn:/etc/getty ttya12 H
    Xx02:23:respawn:/etc/getty ttyb02 H

    Note: The numbers associated with each "tty" represent port number (ttya01 is Port 1, ttya08 is Port 8).
  4. The last number or letter (H in the previous example) is an index into the /etc/gettydefs file, which may be set to any of the allowable baud rates (check your operating system's manual.). In this case, H specifies 9600 baud, 8 data bits, 1 stop bit, and no parity.
  5. Enter this command at a root prompt: init q
  6. Modify the file /usr/lib/uucp/Devices.  Add an entry for the device at the end of the file like this:

    Direct cua12 - 38400 direct
  7. Comment out any ACU lines relating to this device until dialin is working properly.

    Note: An ACU line is necessary for correct operation of the modem in dialout applications. Refer to your modem manual or to the modem manufacturer for the correct initialization string to use for your modem. Refer to your operating system documentation for guidance on setting up an appropriate ACU entry that uses this initialization string.
  8. Connect to the modem by entering this command at a root prompt:

    cu -l /dev/cua12 -s 38400
    at&w [train modem to port speed]

    Note: In HP-UX, the TTY device name is for dial-in, the cu name is for dial-out.
  9. To exit cu, enter:

~. (a tilde followed by a period)