A 150-mW subscriber-line-board controller

A line circuit-board controller for digital exchanges is presented. The system, circuit, and technological aspects of the design are discussed. The dual-processor terminal controller (DPTC) interfaces serially with two independent exchange processors and up to 16 subscriber-line circuits. The device interfaces to time-division multiplex links, handles control and signaling in dedicated channels, has the ability to sense change in the subscriber-line status, and provides data switching for the 16 subscriber-line circuits. An analog PLL circuit builds the 4-MHz local timing out of the two asynchronous exchange clocks. In order to achieve low power consumption and minimal area, all the circuitry is implemented using clocked dynamic CMOS.