The DTP field can be structured four different ways, depending on the device associated with the entry:
Directly connected modem
If a modem is connected directly to a port on your computer, the DTP field of the associated Devices file entry has only one pair. This pair would normally be the name of the modem. This name is used to match the particular Devices file entry with an entry in the Dialers file. Therefore, the Dialer field must match the first field of a Dialers file entry as shown in Example 12-7. (The titles of each column apply only to fields in the Devices file.)
File Name Type Line Line2 Class Dialer-Token-Pairs Devices ACU cua/b - 2400 hayes Dialers hayes =,-, "" \\dA\pTE1V1X1Q0S2=255S12=255\r\c \EATDT\T\r\c CONNECT
Notice that only the dialer portion (hayes) is present in the DTP field of the Devices file entry. This means that the token to be passed on to the dialer (in this case the phone number) is taken from the Phone field of a Systems file entry. (\T is implied, as described in Example 12-9.)
Direct link - For a direct link to a particular computer, the DTP field of the associated entry would contain the keyword direct. This is true for both types of direct-link entries, Direct and Sys-Name (refer to "Type Field").
Computers on the same port selector - If a computer with which you want to communicate is on the same port selector switch as your computer, your computer must first access the switch. The switch then makes the connection to the other computer. This type of entry has only one pair. The dialer portion is used to match a Dialers file entry as shown in Example 12-8. (The titles of each column apply only to fields in the Devices file.)
File Name Type Line Line2 Class Dialer-Token-Pairs Devices develcon cua/a - 1200 develcon Dialers develcon ,"" "" \pr\ps\c est:\007 \E\D\e \007
As shown, the token portion is left blank. This indicates that it is retrieved from the Systems file. The Systems file entry for this computer contains the token in the Phone field, which is normally reserved for the phone number of the computer. (Refer to "/etc/uucp/Systems File".) This type of DTP contains an escape character (\D), which ensures that the contents of the Phone field not interpreted as a valid entry in the Dialcodes file.
Modems connected to port selector - If a high-speed modem is connected to a port selector, your computer must first access the port selector switch. The switch makes the connection to the modem. This type of entry requires two dialer-token-pairs. The dialer portion of each pair (fifth and seventh fields of entry) is used to match entries in the Dialers file, as shown in Example 12-7. (Notice that the titles of each column apply only to fields in the Devices file.)
File Name Type Line Line2 Class Dialer-Token-Pairs Devices ACU cua/b - 1200 develcon vent ventel Dialers develcon "" "" \pr\ps\c est:\007 \E\D\e \007 Dialers ventel =&-% t"" \r\p\r\c $ <K\T%\r>\c ONLINE!
In the first pair, develcon is the dialer and vent is the token that is passed to the Develcon switch to tell it which device (such as Ventel modem) to connect to your computer. This token is unique for each port selector since each switch can be set up differently. After the Ventel modem has been connected, the second pair is accessed, where Ventel is the dialer and the token is retrieved from the Systems file.
Two escape characters can appear in a DTP field:
\T - Indicates that the Phone (token) field should be translated using the /etc/uucp/Dialcodes file. This escape character is normally placed in the /etc/uucp/Dialers file for each caller script associated with a modem (Hayes, US Robotics, and so on). Therefore, the translation does not take place until the caller script is accessed.
\D - Indicates that the Phone (token) field should not be translated using the /etc/uucp/Dialcodes file. If no escape character is specified at the end of a Devices entry, the \D is assumed (default). A \D is also used in the /etc/uucp/Dialers file with entries associated with network switches (develcon and micom).