IBM-PC/XT异步通信适配器采用INS8250串口通信芯片,她是构成RS-232C标准通信电压接口的核心部分部件，再加上RS-TTL电平转换芯片SN75150（TTL- RS-232）或MC1488和SN75154（RS232- TTL）或MC1489就实现INS8250异步收发器TTL电平与RS232电平之间的相互转换。-IBM-PC/XT asynchronous communications adapter with INS8250 serial communication chips, she constitutes a standard RS-232C communication interface, the core voltage components, together with RS-TTL level conversion chip SN75150 (TTL-RS-232) or MC1488 and SN75154 (RS232-TTL) or MC1489 to achieve INS8250 UART TTL level and RS232 level conversion between.