Envoy ACP/XF Application Programming Manual

EnvoyACP/XF and the Application Task
EnvoyACP/XF Application Programming Manual–132179
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Your Application and V.25 bis
The contents of V.25 bis communications are made up of ASCII strings that handle the
call-establishment (such as providing the number to be dialed) and call-clearing (such as
handling call failure) functions.
Some V.25 bis commands specify dialing calls to a preprogrammed or stored telephone
number. The modem determines the scope of V.25 bis commands (issued from the DTE)
and indications (responses from the modem). Refer to your modem manual for details.
All V.25 bis implementations must support the minimum set of V.25 bis commands and
indications, as required by the CCITT (see Table 1-1
).
The DTE and DCE pass the commands and indications in unnumbered information (UI)
frames that adhere to the ANSI X3.66 frame format.
Figure 1-3
shows the frame format for V.25 bis and the source of each frame. Further
information on procedure calls is provided in the examples that follow the figure.
Your Application and V.25 bis
When a line has been defined for V.25 bis mode, your application can generate
commands and responses to the modem by issuing appropriate sequences of the
Guardian procedure calls FILE_OPEN_, SETMODE, DEFINELIST, CONTROL,
READ, and WRITE.
Table 1-1. V.25 bis Commands and Indications
Command/Indication Description
CIC Connect incoming call.
CFI Call failure (such as no answer or line busy).
CRNnnnnnn Call request with number provided, where nnnnnn = number to
be dialed.
DIC Disregard incoming call.
INC Incoming call indication.
INV Invalid command received (syntax error).
VAL Valid command acknowledged.
Figure 1-3. V.25 bis Frame Format
053
F A C
message
FCS F