1. ACLI Configuration Guide
  2. DTMF Transfer and Support
  3. DTMF Transfer Hardware Processing

DTMF Transfer Hardware Processing

DTMF transfer processing, the conversion between two DTMF transfer types, occurs in either the transcoding NIU’s Digital Signal Processors (DSPs) or the Network Processors (NPs). Understanding where the processing takes place is important to determine which subsystem uses extra processing load per conversion.

There are a few rules you can use to determine which subsystem performs the DTMF transfer processing:

  • If audio transcoding is enabled for the call, DTMF transfer processing occurs in the transcoding modules.
  • If DTMF audio tones are generated from RFC 2833 or from signaling messages (SIP INFO), DTMF transfer processing occurs in the transcoding modules.
  • If the global translate non inband event parameter is enabled, DTMF transfer processing occurs in the transcoding modules.
  • If signaling to RFC 2833 processing occurs in either direction of the call, and the previous 3 conditions are not valid, DTMF transfer processing occurs in the NPs.