RS-232C interface definition (DB9 and db25) commonly used pin Definition

RS-232C interface definition (DB9) PIN definition symbols 1 Carrier Detection DCD (data carrier detect) 2 receive data rxd (received data) 3 send data txd (transmit data) 4 data terminal prepare DTR (Data Terminal ready) 5 signal SG (signal ground) 6 data prepare DSR (data set ready) 7 request to send RTS (request to send) 8. Clear send CTS (clear to send) 9. The ring indicator prompt is Ri (ring indicator)1. description of common signal ports of DB9 and db25 9-pin serial port (DB9) 25-pin serial port (db25) feature description: Data Carrier Detection DCD 8 Data Carrier Detection DCD 2 receive data rxd 3 receive data rxd 3 send data txd 2 send data txd 4 data terminal preparation DTR 20 data terminal prepare DTR 5 signal ground Gnd 7 signal ground Gnd 6 data device prepare DSR 6 data prepare DSR 7 Request send RTS 4 request send RTS 8 clear send CTS 5 clear send CTS 9 ring number indicates Dell 22 ring number indicates dell