Overview
The
supports pass-through of the text media streams based on the T.140 codec. The
t140Call flag is added to the Packet Service Profile to support T.140 calls.
The
supports:
- Calls with only T.140 stream.
- T.140 stream pass-through when it is part of multiple stream sessions (audio and Video calls).
- SDP update in 200 OK for T.140 streams (controlled by the flag
sendUpdatedSdpIn200Ok in the ingress IP attributes). - Direct Media calls with T.140 streams.
- Late media pass-through calls with T.140 streams.
- Downstream forking calls with T.140 streams.
- Ring Back Tone (RBT) call flows, all types of direct media, LI, SRTP/DTLS pass-through calls with T.140 streams.
The following session modifications are supported for the T.140 sessions:
- Addition and/or removal of T.140 streams.
- Modification triggered due to change in T.140 stream attributes.
- Modification triggered due to changes in session attributes for non-T.140 stream related attributes.
| Note |
|---|
The does not validate, prioritize, or purge any codec or attributes received for the text media. Any validation required is performed by the endpoints. |
Text Codecs SIP
The
relays text codec by default using dynamic payloads.
Text Codecs T.140
The
supports the following codec for text call scenarios (that is, Text - Text calls with an audio and video stream).
Table 1: Supported Supported Codecs for Text CallCalls
| Codec Variant | Payload Type |
|---|
| T.140 | Dynamic |
| T.140 | - T.140 to TTY Transcoding (DSP) for SIP
- T.140 to TTY Transcoding support in DSPs (SBC 5400 Series and SBC 7000)
- T.140-to-TTY Transcoding for the SBC SWe.
|
T140 Passthrough
The
supports T.140 passthrough calls over GW-GW interface between the
(
-
).