A.1 GTT-Voice specific information for CTM support in, or associated with, all transcoders in the access network for GSM networks with A-interface

23.2263GPPGlobal Text Telephony (GTT)Release 17Stage 2TS

The CTM detection/conversion function may be incorporated in all transcoders where CTM activity can realistically be expected. It is also an option to incorporate a CTM detection/conversion function in a separate entity associated with the Transcoder.

The CTM adapter automatically detects the presence of CTM encoding and provides the necessary conversion to the appropriate ITU‑T Recommendation V.18 [4] modem encoding.

Figure A.1: Association of a CTM adapter with the transcoder in the access network

Due to the presence of the CTM detection/conversion function in all circuits, no CTM capability information needs to be signalled to the network by the mobile.