Patent ID: 7277490

Claim:
An apparatus for converting pulse code modulation (PCM) signals from either one of two different modulation standards to the other one of said two different modulation standards in a system characterized by having a plurality of communication channels with each channel having a plurality of input digital signals modulated by said one of said two different modulation standards, said apparatus comprising: a channel selector for generating a channel select signal for identifying one of said plurality of communication channels in said system; at least one codec means for selectively converting said identified input digital signals received in said one of said plurality of communication channels from said one of said two different modulation standards to the other one of said two different modulation standards in response to said channel select signal; and, a plurality of mixers for selectively releasing and transmitting said input digital signal modulated by said one of said two different modulation standards and said converted input digital signal to the other one of said two different modulation standards by said codec means in response to said channel select signal, wherein said mixer further comprises a first buffer for receiving said converted input digital signal by said other one of said two different modulation standards from said codec means, and a second buffer sharing an output terminal with said first buffer for receiving said input digital signal modulated by said one of said two different modulation standards.