US Patent 7277490 Apparatus for converting PCM signal

An apparatus for converting pulse code modulation (PCM) signals in a telecommunication system between two different modulation standards. In the apparatus, a channel selector generates a channel select signal for identifying at least one channel of the multiple channels containing input digital signals modulated by said one of said two different modulation standards. A first codec demodulates a signal on a channel designated by the channel select signal which is modulated by the first modulation standard, into an analog signal to be supplied to a second codec, which modulates the converted analog signal input into a digital signal using the second modulation standard. The reverse process is executed in a similar manner. A second codec using the second modulation standard demodulates a digital signal on the channel designated by the channel select signal into an analog signal to be supplied to the first codec, and the first codec in turn modulates the converted analog signal into a digital signal using the first modulation standard. As a result, the present invention is able to convert pulse code modulation signals from either one of two different modulation standards to the other one of said two different modulation standards in a telecommunication system.