Abstract: A method and system are provided for preventing data loss in a VoIP system. In particular, during a VoIP call, it is determined whether incoming ringing on a POTS line causes an unacceptable level of signal loss or errors. If so, for subsequent VoIP calls, the CO handling calls to the POTS line is instructed to either answer each call with a busy signal or automatically forward calls to the POTS line to the VoIP line or other selected telephone. Calling returns to normal upon ending of the VoIP call. In this manner, incoming ringing on the POTS line does not result in call dropping or lengthy retraining processes.

Abstract: A multi-rate encoder and decoder system is disclosed. The multi-rate encoder and decoder system is capable of operating with a mother code or a subset code of the mother code and includes a trellis encoder having a set of inputs and a set of outputs corresponding to the mother code and a select unit capable of removing the set of inputs into the trellis encoder that correspond to the mother code but not the subset code prior to encoding. The multi-rate encoder and decoder system further includes a decoder having a set of decoder inputs and a set of decoder outputs corresponding to the mother code and a decoder select unit capable of ignoring transitions in the trellis code produced by the encoder that belong to the mother code but not to the subset code.