Voice over pcm technique providing compatibility between pcm data and lower ratevocoder data

摘要

A method and system are disclosed for transmitting a digital representation of voice data. A first step of the method includes sampling and digitizing a voice signal and generating a first data stream having a bit rate of X bits per second (e.g., 4kbps or lower). A next step converts the first data stream to a second data stream having a bit rate of Y bits per second (e.g., a 64kbps PCM data stream). A next step overlays individual ones of bits of the first data stream onto predetermined ones of bits of the second data stream (the Q0 bits of preferably, every other PCM sample) to form a modified data stream (a VoPCM data stream in accordance with this invention). A next step transmits the modified data stream to a receiver, such as through a circuit-switched PSTN connection and/or a packet-switched TCP/IP (Internet) connection. The method further includes a step of processing the received modified data stream. In one embodiment the receiver extracts the first data stream (desired voice codec data) from the predetermined ones of the bits of the modified data stream, such as from the LSB of every other PCM sample.