Abbreviation Name (9-pin connector) RS-232 CCITT JIS 5 AB (GND) 102 SG Signal ground 3 BA (TXD) 103 SD Transmitted data 2 BB (RXD) 104 RD Received data 7 CB (CTS) 105 RS Request to send 8 CA (RTS) 106 CS Clear to send Signal Wiring Example The pin numbers are for the 9-...