Abstract: A method of data communication, particularly for long data messages, is disclosed. The data code words of a message are arranged in segments, each with its own header, and are assigned message and segment identification. A receiver reconstructs the data message segment by segment and, in the non-group call situation, transmits an acknowledgement after the receipt of a segment. The receiver comprises a resettable timer which is set on the receipt of an acceptable segment and runs for a pre-determined duration. If another segment is received within the duration of the timer and has the same identification as the acceptable segment, then it is treated as a retransmission. Efficiency of the data communication method can be increased by retransmitted data code words being included with new data code words in a segment rather than being transmitted in a separate segment requiring its own header. Optionally, an efficient form of bit interleaving may be used.