A digital communications system for delivering data blocks includes at least one transmit/receive unit (TRU). The TRU includes a storage element for receiving transmit data packets and retransmit data packets from a sending unit and a processing element communicatively coupled to the storage element. The processing element is configured for recognizing a failure to receive at least one other transmit data packet (missing data packet) from the sending unit, and for configuring a status control packet for transmission to the sending unit, the control packet includes a header including a next packet identifier for a next data packet anticipated to be received and a status payload portion including a missing packet identifier including the transmit packet identifier for the missing data packet. In the system, the retransmit data packet includes at least a segment of the data payload in the missing data packet associated with the missing packet identifier.