US Patent 7746881 Mechanism for modem pass-through with non-synchronized gateway clocks

A method for compensating for asynchronous clock sources is presented. A buffer is provided for storing frames received from a packet network. The buffer having a preselected playout delay. Upon detecting a buffer overflow, a drain operation is performed on the buffer and the playout delay is modified to provide a sufficient number of buffer locations for frames to be stored. Upon detecting a buffer underflow, a fill operation is performed on the buffer and the playout delay is modified to provide a sufficient number of frames to be played out.