JPS5850464B

PURPOSE:To obtain an error resending request function with transmission efficiency improved sacrificing a little reliability by stopping the transmission of a few error detection signals, even if detected, to a transmission part and 2nd memory unit. CONSTITUTION:Discriminator 26 in reception part 2 selects a desired detection code among detection signal output 21 from demodulator 17 and its output 27 is applied to 2nd modulator 23 and 2nd memory unit 19. On the input of error detection signal 21, quinary counter circuit 28 starts counting pulses of signal 21. Since ouput 32 of inverter 29 is ''1'' unitl the output of quinary counter circuit 28 reaches ''1'', AND gate 31 stays open and signal 21 itself is output 27 of discriminator 26. Once circuit 28 counts the pulses of signal 21 five times, output 30 of circuit 28 becomes ''1'' and output 32 of inverter 29 becomes ''0'' to close AND gate 31, so that the 5th pulse of signal 21 will never appear at output 27 of discriminator 26.