Abstract: A method for re-establishing communication between a base station (102) that transmits on a forward channel, and a subscriber unit (108) that has temporarily lost the forward channel, uses the concept of a re-registration interval. The base station (102) transmits, to subscriber units (106, 108) in its area, a signal indicating the duration of a re-registration interval. A subscriber unit that has temporarily lost the forward channel determines whether the duration of such loss exceeds the re-registration interval. If the interval is exceeded, the subscriber unit sends a re-registration signal to the base station on a reverse channel. A selective call transceiver (400) is programmed to operate as a subscriber unit that uses the re-registration interval.

Abstract: A method for re-establishing communication between a base station (102) that transmits on a forward channel, and a subscriber unit (108) that has temporarily lost the forward channel, uses the concept of a re-registration interval. The base station (102) transmits, to subscriber units (106, 108) in its area, a signal indicating the duration of a re-registration interval. A subscriber unit that has temporarily lost the forward channel determines whether the duration of such loss exceeds the re-registration interval. If the interval is exceeded, the subscriber unit sends a re-registration signal to the base station on a reverse channel. A selective call transceiver (400) is programmed to operate as a subscriber unit that uses the re-registration interval.

Abstract: A synchronous communications multiplexer for connecting a plurality of synchronous communications lines to an MP (multi-purpose) bus. In its basic form, the multiplexer is capable of handling bit oriented protocols (BOP) and is capable of being upgraded to support byte-oriented protocols. The present invention supports full- or half-duplex data rates of up to 19,200 baud. Total throughput, when operating with four ports (as an example), is in the range of 76.8 kbits/sec. A special mode of operation (unisync) allows operating a single port at 56 kbits/sec., full duplex. Other capabilities include software-selection of parameters (such as baud rate) and operation in a "transmitter queueing" mode of operation.