Abstract: A multiline PCM interface for signal processing is of particular application in cordless digital telephony, type DECT, with echo cancelling and ADPCM type voice encoding. The interface incorporates a set of ADPCM encoders (COD) and ADPCM decoders (DEC), digital-to-analogue (D/A) converters and analogue-to-digital converters (A/D). The outputs of the ADPCM decoders (DEC) and the analogue-to-digital converters (A/D) are joined to form a PCM output bus (BPO), the inputs of the digital-to-analogue (D/A) converters and ADPCM encoders (COD) are joined together to form a PCM input bus (PI). The interface also includes signal processing means (MSP) which receive data bursts from the PCM output bus (BPO) and applies these same bursts to the PCM input bus (PI) with a delay of one frame and echo-free. A synchronism generator (SYGEN) allocates consecutive time slots to converters involved in the same conversation, which therefore employ the same signal processor (DSP) to perform associated conference operations.