DSS.1 Finite State Machine ,base: ITU-T Rec Q.931

This class provides methods to play DTMF tones (ITU-T Recommendation Q.23), call supervisory tones (3GPP TS 22.001, CEPT) and proprietary tones (3GPP TS 31.111). Depending on call state and routing options, tones are mixed to the downlink audio or ou

code to decode ITU Q.931 call control messages.

ANSI T1.617 Annex D or ITU-T Q.933 Annex A.