SCO OpenServer Handbook
Chapter 24, Adding modems
Creating a new atdial dialer

Creating a new atdial dialer

You can create a new atdial dialer without having the SCO OpenServer Development System installed. An atdial dialer is actually a link to the binary /usr/lib/uucp/atdialer that calls a configuration file in the /usr/lib/uucp/default directory. The configuration file contains all the commands specific to that modem. For example, atdialHAY is linked to atdialer and the configuration file is in /usr/lib/uucp/default/atdialHAY. To create a new atdial dialer, atdialMINE for example, follow these steps:

  1. Log in as root.

  2. Copy one of the atdial* files in /usr/lib/uucp/default to use as a template for the new configuration file atdialMINE in the same directory. For example, to use atdialW96 as the template, enter:

    cp /usr/lib/uucp/default/atdialW96 /usr/lib/uucp/default/atdialMINE

  3. Edit /usr/lib/uucp/default/atdialMINE to add and alter the parameters that are appropriate for your modem. See the atdialer(C) manual page for more information.

  4. Create a symbolic link /usr/lib/uucp/atdialMINE to /usr/lib/uucp/atdialer using the command:

    ln -s /usr/lib/uucp/atdialer /usr/lib/uucp/atdialMINE

When you invoke atdialMINE, atdialer reads the /usr/lib/uucp/default/atdialMINE file.

Alternatively you can use the make.dialer script to create an atdial dialer. See make.dialer(C) for more information. 

Setting up the modem for FAX/DATA detection

Set the MDM_MODE parameter in /usr/lib/uucp/default/atdial* to ``AUTO'' to configure a modem to detect incoming FAX messages automatically. Use the -f option with the getty(M) program defined for the modem port to invoke an appropriate program defined in /etc/gettyacts (see gettyacts(F)) if an incoming connection is a FAX message or another communications protocol such as PPP. 

Editing connect speed strings

Most modern modems can perform speed conversion which allows them to negotiate a different connection speed with the remote modem than the serial line speed that they use with the local computer.

If you use hardware flow control with the modem, and the modem is capable of performing speed conversion, do not use the RTC_speed strings. Instead, use the RTC_CONNECT string and set it to the value ``CONNECT''. This will give you the fastest available connection speed. The computer to modem speed will be set by the value in the /usr/lib/uucp/Devices file.

The RTC_speed strings in the /usr/lib/uucp/default/atdial* configuration files allow the dialer to recognize connect messages from the modem and map them to appropriate speed(s). For example: 

   RTC_9600=CONNECT 9600
The dialer then recognizes ``CONNECT 9600'' as a 9600bps connection. The connect messages for each speed must be unique. If the message is set to ``CONNECT'', the first speed mapped to the connect message is used. For unused speeds, simply set the RTC_speed string to ``not used'', for example: 
   RTC_300=not used
It is possible to specify all valid connect messages. For example: 
   RTC_2400=CONNECT 2400
   RTC_9600=CONNECT 9600
For a modem that performs speed conversion, this more accurate setup is only necessary if you need to guard against long UUCP transfers at 2400bps. This is because the speed recognized by the dialer is matched against the speed range in the Systems file or the speed range on the cu command line. If it is out of range, an EXECDIAL LOCAL FAILURE will result. In the following command the speed range specified is 9600 - 9600:

cu -ltty1A -s9600 5551212

Connections at 2400bps using the above command will fail if separate RTC_speed lines are set up. Either of the following commands allow a 2400bps connection in this case:

cu -ltty1A -s2400 5551212

cu -ltty1A -s2400-9600 5551212