PURPOSE: To send out new data and to improve transmission efficiency by resending only data of a terminal equipment which has no error checking function when an error in the transmission of multiplex data occurs.
CONSTITUTION: When a multiplex signal M1 is received by a receiving station 2, circulation redundancy is checked on the basis of data a1∼d1 and an error check code. The receiving station 2 checks the multiplex signal M1 from a transmission and reception part 15 by a checking part 16 and generates error signals E1 and E2 when an error is detected. The data a1∼d1 received by the transmission and reception part 15 are distributed by a distribution part 17 to receiving registers 18∼21, where they are set. A control part having received the error signal E1 generates a shift pulse S2. Consequently, the data a1 in the register 18 is shifted to a distribution register 23 and then sent out to a terminal equipment A' having an error checking function. A request-to-resend transmission part 27 having received the error signal E2 sends out a request-to-resend signal Q. A transmitting station 1 once receiving the signal Q resends the data b1∼d1 and transmits a signal M2 containing new data a2.
TANAKA HIROYA
ASAHINA TAKESHI
