ECBM--Low-Cost Echo Canceller in a Silicon Boutique for Terminals, PBX´s and CO Access

The echo canceller burst mode (ECBM) is part of a "silicon boutique," a family of devices that offer a cost-effective industrial solution to the problem of ISDN basic access. ECBM takes advantage of both the echo cancellation and the time compression techniques. It leaves a silent period in each direction of transmission; this creates periods in which only the received signal or only the echo is present, which greately simplifies the echo canceller and the timing recovery. The components of the family implement the signal processing, power feed, and line interface functions needed for the ISDN basic access (144 kbits/s); they take into account the requirement of different connection schemes, yet offering flexibility to accommodate possible standards evolution. Their coordination avoids "glue" components and facilitates some basic access functions (e.g., activation, maintenance, monitoring).