PURPOSE: To normally reproduce a digital code by providing a first detecting means to detect potential difference between a pair of lines by a first threshold value as a positive value, and a second detecting means to detect it by a second threshold value as a negative value.

CONSTITUTION: A reception circuit 10 of a node to be connected to a local area network (LAN) is composed of a comparator 15 having the threshold value of ΔV, comparator 16 having the threshold value of -ΔV, inverters 17, 19 and 21, RS (RESET SET) flip-flop 18, OR gate 20 and transfer gates 22 and 23. Therefore, even when the state of clamping either a fail (+) wire line or a (-) wire line at an arbitrary potential from GND to Vcc is generated at a transmission line 6 of a dual wire line composed of the (+) side wire line and the (-) side wire line, the digital code is exactly received. Thus, the digital code is normally reproduced.