Abstract: A synchronized communications system permits resynchronization in late-entry or fade-recovery conditions. A plurality of communications devices are operative for communicating in a synchronized, encrypted communications channel between each other. At least one of the communications devices is operative for continuously transmitting a resynchronization header that includes a start-of-message field that includes voice or data message information type, a message indicator field, a synchronization check field, a first error correction field computed over the start-of-message/message indicator/synchronization fields, a frame index field and a second error correction field computed on the frame index field. Receivers monitor the channel to decode these headers to perform late-entry or fade recovery.

Abstract: A system communicates with a mobile radio and includes a repeater that is operative for transmitting and receiving communications signals on respective first and second frequency hopping hopset. A mobile radio receives a communication signal from the repeater on the first frequency hopping hopset and transmits a communication signal to the repeater on the second frequency hopping hopset.