Using “D” Messages for Layer 3• 8-12 •
The H.110 Basic Rate ISDN Board
Text can be sent as part of the SETUP message by filling the buffer as
described above before sending the “DS” command. The buffer is checked
to automatically include any text when the SETUP message is composed.
The buffer is cleared when a call is released on that B-channel.
It is also possible to include a single line of text in a PROGress message by
sending a command of the form DPxxPpsT(text) where p is the progress
indicator and s is the signal.
Text that is sent to a port set as a TE will be passed to the application in a
response message of the form DTxxLl(text) where l is the line number and
xx is the B channel associated with either the call or the SPID. A single line
of text in an ALERTing or PROGress message will become part of the
“DA” or “DP” message after the signal character.
8.7 NT Call Handling Examples
This section and the one that follows will give some simple examples of the
“D” messages that would be sent and received for a typical speech call.
Only the “D” messages are shown. The “C” messages used to establish the
audio paths will be explained in section 9.0.
8.7.1 A Call Terminating at a Terminal
In this example, a call is placed to an ISDN terminal, is answered, and then
disconnected by the terminal hanging up. The B1 channel of the fourth
BRI port is used.
commands responses description
DS06SNN7654321 SETUP message
DA0603 ALERTing message
DC0603 CONNect message
DD0610 DISConnect message
DR060F RELease COMplete
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