PURPOSE: To obtain the multiplex transmission system in which the transmission reliability is high, the transmission speed is fast, number of transmission lines is less and a short-circuit of the transmission line is simply detected.
CONSTITUTION: A transmitter 12 sends a transmission signal TS in the voltage mode in which '0', '1' of transmission data are expressed by a narrower and a wider pulse width complementary data are respectively added just after transmission data, and a start synchronizing signal is added to its head. A data discrimination section 60 of a receiver 14 uses an up-down counter to discriminate whether the data are '0' or '1', a complementarity check section 62 checks the complementarity between transmission data and their complementary data and uses a switch circuit 66 to return a reply signal RS in the current mode for a start synchronization period in a succeeding communication cycle when the complementarity is all normal. A reply discrimination section 32 in the transmitter 12 monitors a voltage V1 across a resistor 36 to detect the return of the reply signal RS and then a short-circuit of a transmission line 16.
YOSHIDA KOJI
TAKEDA YASUHITO
