AudioCodes Mediant 500 E-SBC User Manual page 739

User's Manual
Parameter
Web/EMS: TGRP Routing
Version 6.8
possible). The Contact header in the outgoing SIP INVITE (Tel-to-
IP call) contains "tgrp=<source trunk group ID>;trunk-
context=<gateway IP address>". The <source trunk group ID> is
the Trunk Group ID where incoming calls from Tel is received. For
IP-Tel calls, the SIP 200 OK device's response contains
"tgrp=<destination trunk group ID>;trunk-context=<gateway IP
address>". The <destination trunk group ID> is the Trunk Group ID
used for outgoing Tel calls. The <gateway IP address> in "trunk-
context" can be configured using the SIPGatewayName parameter.

[3] Hotline = Interworks the hotline "Off Hook Indicator" parameter
between SIP and ISDN:

For IP-to-ISDN calls:
- The device interworks the SIP tgrp=hotline parameter
(received in INVITE) to ISDN Setup with the Off Hook Indicator
IE of "Voice", and "Speech" Bearer Capability IE. Note that the
Off Hook Indicator IE is described in UCR 2008 specifications.
- The device interworks the SIP tgrp=hotline-ccdata parameter
(received in INVITE) to ISDN Setup with an Off Hook Indicator
IE of "Data", and with "Unrestricted 64k" Bearer Capability IE.
The following is an example of the INVITE with tgrp=hotline-
ccdata:
INVITE sip:1234567;tgrp=hotline-ccdata;trunk-
context=dsn.mil@example.com

For ISDN-to-IP calls:
- The device interworks ISDN Setup with an Off Hook Indicator
of "Voice" to SIP INVITE with "tgrp=hotline;trunk-
context=dsn.mil" in the Contact header.
- The device interworks ISDN Setup with an Off Hook indicator
of "Data" to SIP INVITE with "tgrp=hotline-ccdata;trunk-
context=dsn.mil" in the Contact header.
- If ISDN Setup does not contain an Off Hook Indicator IE and
the Bearer Capability IE contains "Unrestricted 64k", the
outgoing INVITE includes "tgrp=ccdata;trunk-context=dsn.mil".
If the Bearer Capability IE contains "Speech", the INVITE in this
case does not contain tgrp and trunk-context parameters.

[4] Hotline Extended = Interworks the ISDN Setup message's
hotline "OffHook Indicator" Information Element (IE) to SIP
INVITE's Request-URI and Contact headers. (Note: For IP-to-ISDN
calls, the device handles the call as described in option [3].)

The device interworks ISDN Setup with an Off Hook Indicator
of "Voice" to SIP INVITE Request-URI and Contact header with
"tgrp=hotline;trunk-context=dsn.mil".

The device interworks ISDN Setup with an Off Hook indicator of
"Data" to SIP INVITE Request-URI and Contact header with
"tgrp=hotline-ccdata;trunk-context=dsn.mil".

If ISDN Setup does not contain an Off Hook Indicator IE and
the Bearer Capability IE contains "Unrestricted 64k", the
outgoing INVITE Request-URI and Contact header includes
"tgrp=ccdata;trunk-context=dsn.mil". If the Bearer Capability IE
contains "Speech", the INVITE in this case does not contain
tgrp and trunk-context parameters.
Note: IP-to-Tel configuration (using the PSTNPrefix parameter)
overrides the 'tgrp' parameter in incoming INVITE messages.
Determines the precedence method for routing IP-to-Tel calls -
739
53. Configuration Parameters Reference
Description
Mediant 500 E-SBC