Method and apparatus supporting TDD/TTY modulation over vocoded channels

An apparatus comprising:

• means for encoding a low activity communication signal using channel coding redundancy and vocoder signatures, wherein sequenced bits contained within the vocoder signatures are spaced further apart than sequenced bits contained within standard vocoder parameters;
• means for transmitting a first frame containing a sequence of bits representing the encoded low activity communication signal to a destination;
• and
• means for decoding the first frame at the destination to retrieve the sequence of bits representing the low activity communication signal, comprising:
• means for comparing a sequence of bits in the received first frame with a known sequence of bits representing the low activity communication signal to identify the sequence of bits used by the first vocoder to encode the low activity communication signal.

A machine-readable medium comprising instructions which, when executed by a machine, cause the machine to perform operations including:

• encoding a low activity communication signal using channel coding redundancy and vocoder signatures, wherein sequenced bits contained within the vocoder signatures are spaced further apart than sequenced bits contained within standard vocoder parameters;
• transmitting a first frame containing a sequence of bits representing the encoded low activity communication signal to a destination;
• and
• decoding the first frame at the destination to retrieve the sequence of bits representing the low activity communication signal, comprising:
• comparing a sequence of bits in the received first frame with a known sequence of bits representing the low activity communication signal to identify the sequence of bits used by the first vocoder to encode the low activity communication signal.