Adding and configuring modems

atdialer

The dialer binaries are named atdial and reside in /etc/uucp. These dialers (for example, Courier_V-34_Data_Fax_Modem) are implemented as symbolic links to a single executable (/usr/lib/uucp/atdialer) together with an editable configuration file in /etc/uucp/default.

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 /etc/uucp/Devices file.

The RTC_speed strings in the /etc/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. In the following command the speed range specified is 9600

9600:

cu -l tty00m -s 9600 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 -l tty00m -s 2400 5551212
cu -l tty00m -s 2400-9600 5551212