Patent ID: 6882969

Claim:
Digital circuit multiplication equipment having a tandem passthrough function of carrying out passthrough transmission of a coded speech signal, and a variable bit rate function of varying a transmission bit rate of the coded speech signal in accordance with a load on the equipment, said digital circuit multiplication equipment comprising: dummy data adding means for generating a pseudo-speech signal with a predetermined transmission bit rate by adding dummy data including coding bit rate information to a coded speech signal supplied from a transmission line, and for supplying the pseudo-speech signal to a tandem circuit switch; speech signal extracting means for extracting a coded speech signal from a pseudo-speech signal supplied from said tandem circuit switch; bit rate identification information adding means for adding bit rate identification information to the coded speech signal extracted by said speech signal extracting means; and speech signal output means for selecting, with reference to coding bit rate information included in the pseudo-speech signal, one of the coded speech signal extracted by said speech signal extracting means and the coded speech signal including the bit rate identification information added by said bit rate identification information adding means, and for delivering the selected coded speech signal to the transmission line.