METHOD FOR COMMUNICATING USING 3 STATE SWITCH BUFFER AND 3 STATE SWITCH BUFFER CIRCUIT FOR PERFORMING THE SAME

摘要

PURPOSE: A method of communications with a three state switch is provided to separate command codes of external devices from data coming through a single line, and to provide a circuit conducting this process. CONSTITUTION: In a method of communications with a three state switch, a three state switch(200) receives an RS232 signal(110) sent through a transmission terminal(Tx) of a personal computer(100). The three state switch(200) divides, bypasses, and sends the RS232 signal(110) to a data converter(300). The external device command of the RS232 signal is sent to the external device(400) and the external device conducts the command. When the personal computer(100) receives data, the three state switch(200) receives a transmission data(A) and a switch control signal(C) from the data converter(300) and an external device command(B) from the external device. If the switch control signal is 0, the transmission data(C) of the data converter(300) is switched to the receiving terminal(Rx) of the personal computer(100). If the switch control signal is 1, the external device command(B) from the external device is switched to the receiving terminal(Rx) of the personal computer(100).