Abstract: A system and method are described for bit rate detection in a serial data communication system, the system employing a data rate prompt of a pair of opposite value data bits which follow a series of idle bits. In a first embodiment a receiving port employs a clocked delay element and a set of data clock rates, each data clock rate being a multiple N of one of a set of established bit transmission rates, ranging from a highest expected bit rate to a lowest expected bit rate. The bit rate detection method comprises: clocking the delay element at the highest data clock rate, upon the sensing of one of the opposite value data rate prompt bits at the delay element, to step the value of the sensed bit into the delay element. After a predetermined number of data clock pulses have stepped the value of the sensed bit into the delay element, the system compares the bit value at an input to the delay element and the bit value in a bit position of the delay element.

Abstract: A signal repeater for regenerating digitally encoded signals transmitted in bursts over a single pair telephone line to enable simultaneous communication between a telephone central office and any one of up to four subscriber transmitter/receivers. The repeater decouples signals from the line for regeneration thereof and recouples the regenerated signals onto the line. Clock frequency and phase information characteristic of the decoupled signals is derived in order to facilitate accurate regeneration of the signals. The decoupled signals are decoded and then regenerated to replicate the signals originally produced by the telephone central office and subscriber transmitter/receivers respectively. The regenerated signals are then re-encoded and recoupled onto the telephone line.