TTL-LEVEL CONNECTED CIRCUIT BETWEEN A COM-PORT AND SERIAL INTERFACE

摘要

The interface personal computer and the communication device use RS 232C level connection for individually independent serial communication. But a communication device of card type inside the personal computer needs dual RS 232C voltage level drivers. Also, it has the inconvenience of adjusting communication speed and parameters. And RS 232C connection levels require +12V, -12V voltage level supply devices to a disadvantage. Thus, the communication device of the invention is designed to remove RS 232C voltage driver and employ a +5V single power supply to drive it. COM port in initial condition causes error to noise, with reducing error. Personal computers dominate communication speed and parameters, minimize circuits, reduce cost, and upgrade the convenience of using.