White Paper Abstract:
This document provides an overview of the different coder-decoders (codecs) used with Cisco IOS® Voice over IP (VoIP) gateways. In Cisco IOS Software Releases earlier than 12.0(5)T, VoIP gateways supports only the G.729 and G.711 codecs and only one voice/fax-relay call per digital signal processor (DSP). With the introduction of Cisco IOS Software Release 12.0(5)T, Cisco VoIP gateways support a larger number of codecs and DSP modules. They can also support up to four voice/fax-relay calls per DSP.