Patent ID: 6826404
Filing Date: 2004-11-30
Classification: H04Q,H04W

Abstract:
A method for transporting tone signalling information through a GSM Circuit Multiplication Equipment (GCME) link in a Global System for Mobile Communications (GSM) network supporting Tandem Free Operation (TFO) and speech compression modes for the passage of signals through the link, respectively using TFO frames and Transcoder and Rate Adaptation Unit-like (TRAU-like) frames, the method comprising:detecting in a data stream to a local entrance to the GCME link, a tone signal to be transported. coding the detected tone signal into bits of a TFO or TRAU-like frame for sending through the GCME link, including setting bits to mark the frame as containing tone signaling information by setting a bad frame indicator bit (BFI) of the frame to indicate a bad frame and by setting first n bits of a data field of the frame to a predetermined value as a tone signaling header field, and setting bits to identify the detected tone signal, whereby the tone signaling information is transported in-band through the GCME link as a marked TFO or TRAU-like frame, and detecting, at a remote exit from the GCME link, the marked frame and regenerating the tone signal in dependence upon the bits of the marked frame.