Patent ID: 6172978
Filing Date: 2001-01-09
Classification: H04J,H04L,H04Q

Abstract:
An audio tandem relay device for relaying an audio signal inputted from a line as ATM cells to a second audio tandem relay device via an exchange, comprising:a cell disassembly for disassembling a received ATM cells inputted from the line into an encoded audio signal;an audio decoder for decoding the encoded audio signal into the audio signal;a pseudo audio signal generator for generating a pseudo encoded audio signal by converting the encoded audio signal, the pseudo audio signal having a data rate unchanged from that of the encoded audio signal and a transmission rate capable of being handled by the exchange;a first pattern inserter for inserting a first pattern signal into the audio signal so that the second audio tandem relay device may identify that the current transmission is a relay transmission;a second pattern inserter for inserting a second pattern signal into the pseudo encoded audio signal so that the second audio tandem relay device may identify that it is in a relay exchange state;an audio encoder for encoding an audio signal received from the exchange;a transmission rate recoverer for changing the pseudo encoded audio signal when received from the exchange into an encoded audio signal having an original transmission rate;a cell assembly for assembling an ATM cell from the encoded audio signal to output to the line;a first pattern detector for detecting the first pattern signal included in a signal from the exchange;a second pattern detector for detecting the second pattern signal included in a signal from the exchange;a first comfort noise generator for outputting a comfort noise to the line through the cell assembly upon detection of the first pattern signal;a second comfort noise generator for outputting a comfort noise to the exchange through the second pattern inserter upon detection of the first pattern signal;a first switch for switching its connection from the first pattern inserter to the second pattern inserter upon detection of either the first pattern signal or the second pattern signal to thereby connect the second pattern inserter to the exchange; anda second switch for switching its connection from the audio encoder to the transmission rate recoverer upon detection of the second pattern signal to thereby connect the transmission rate recoverer to the cell assembly.