| 摘要 |
PROBLEM TO BE SOLVED: To eliminate erroneous operation due to its own output even if the output section and the input section are connected with a single signal line, and to reduce power consumption. SOLUTION: When a communication means 12 serves as a transmitter and a low level is outputted to the output section Out, collector-emitter of an NPN transistor 14 is brought into interrupted state. A diode 16 is biased forward and brought into conductive state and a current flows from a communication line 11 to the output section Out of the communication means 12 thus bringing the communication line 11 to low level. The current flowing into the communication line 11 is fed from the positive voltage side of a power supply through the collector-emitter of an NPN transistor 15 on the side of the other communication means 13 and a pull-up resistor 19. Logical state at the input section In of the communication means 13 is brought to low level by a voltage drop caused by that current. When a high level is outputted from the output section Out, the communication means 13 can receive a digital signal transmitted from the communication means 12 connected through the communication line 11 at the input section In. COPYRIGHT: (C)2005,JPO&NCIPI
|
