Patent ID: 8265696

Claim:
A digital telecommunications system comprising: (a) a first mobile switching centre configured to enable speech communication between a plurality of terminals, the first mobile switching centre being associated with a calling terminal and including a first transcoder unit; (b) a second mobile switching centre configured to enable speech communication between a plurality of terminals, the second mobile switching centre being associated with a called terminal and including a second transcoder unit, wherein the first and second transcoder units each include speech codecs, in which each of the speech codecs comprises an encoder unit and a decoder unit, wherein the calling and the called terminal each include a respective plurality of supported speech codecs, and wherein the calling terminal and the called terminal are each arranged to provide information regarding the availability of said respective plurality of supported speech codecs to their associated mobile switching centre; (c) the first mobile switching centre being configured to perform handshaking with the second mobile switching centre, the handshaking including indication of the availability of the respective plurality of supported speech codecs supported by the calling terminal, wherein the second mobile switching centre is configured to select a compatible speech codec selected from said respective plurality of available and supported speech codecs of each of the calling and the called terminals to be usable commonly by both the calling and called terminals and convey to the first mobile switching centre information indicating the selected compatible codec, and wherein the first mobile switching centre is configured to convey to the calling terminal the selected compatible speech codec and to establish call connections that bypass one or more of the transcoder units or, to control the transcoder units to transmit encoded speech between the called and calling terminals without performing speech encoding operations so that speech is encoded and decoded only in the called and calling terminals.