Real-time multi-channel monitoring of communications on a T1 span

The evolution of a successful telecommunications monitoring device is described from its inception to its installation across Canada. This product, called the service discrimination unit (SDU), is a powerful and flexible platform for digital processing of signals on a T1 span. Signal processing is provided by Motorola DSP56001 digital signal processors and control functions are provided by Motorola 68HC11 processors. The SDU's first commercial application is to apply the DSP processing power to determine if the traffic being carried on a telephone line is voice, modem data, or facsimile data.< >