PhoneNet and Pager channels use the file phone_list.dat in the PMDF table directory to relate transport methods to certain channels. Each line in this file is referred to as a "method" and has the format

channel device [script [options]]

where channel is the name of a channel, device is a possible device that the channel can use, script is the name used to find the script file, and options are a set of options passed to a user-written command file. The options field is ignored on UNIX platforms.

device is usually, but not always, the name of an asynchronous terminal device. On OpenVMS, it can be a logical name which translates to one or more devices. If options are omitted, an empty set of options is used. If script and options are both omitted an empty set of options are used and script is set to device

The usual form of PMDF comment lines are all allowed in the file. Channel names are not case sensitive. The device, options, and script are not case sensitive on OpenVMS, but are case sensitive on UNIX platforms.

Example 24-1 depicts a typical phone_list.dat file for OpenVMS. Example 24-2 depicts a typical phone_list.dat file for UNIX systems.

Example 24-1 OpenVMS Sample PhoneNet phone_list.dat file

! phone_list.dat - Allow the use of either modem ! for Pager channel. ! There are two numbers to try on P_SMC channel, ! so try it with two different scripts. ! pager_pactel SLOW_MODEM pager_slow pager_pactel AUTO_DIALER pager_fast ! p_smc AUTO_DIALER dial_one p_smc AUTO_DIALER dial_two

Example 24-2 UNIX Sample PhoneNet phone_list.dat file

! phone_list.dat - Allow the use of either slow or fast modem ! for Pager channel. ! There are two numbers to try on P_SMC channel, ! so try it with two different scripts but only on fast modem. ! pager_pactel /dev/ttyd0 pager_slow pager_pactel /dev/ttyd1 pager_fast ! p_smc /dev/ttyd1 dial_one p_smc /dev/ttyd1 dial_two

A channel can have one or more entries associated with it. In the two examples, two entries are present for each channel. For the pager_pactel channel we want to use two different devices. For the p_smc channel we only want to use one device, but we want to try with two different scripts.

On OpenVMS, multiple devices such as a modem pool, can be used by specifying a logical name for device which translates to the list of devices to use. For example, the logical AUTO_DIALER used in Example 24-1 defined as

$ DEFINE/SYSTEM AUTO_DIALER LTA100:,TXA6:,LTA2:,LTA5:

is a search list specifying the four devices LTA100:, TXA6:, LTA2:, and LTA5:.

On UNIX and NT platforms, multiple devices need to be handled with multiple entries in the phone_list.dat file for each channel, one entry per channel per device.