Serial port to serial port. Cable wiring and pinout

Use this cable between two DTE devices (for instance two laptops).

	RS232 port pinout on Side 1
	RS232 port pinout on Side 2

	DB9-1	DB9-2
Receive Data	2	3	Transmit Data
Transmit Data	3	2	Receive Data
Data Terminal Ready	4	6+1	Data Set Ready + Carrier Detect
System Ground	5	5	System Ground
Data Set Ready + Carrier Detect	6+1	4	Data Terminal Ready
Request to Send	7	8	Clear to Send
Clear to Send	8	7	Request to Send

Use this cable between two devices: DTE and DCE (for example, a computer and a printer).

	DB9	DB25
Receive Data	3	3	Transmit Data
Transmit Data	2	2	Receive Data
Clear To Send + Data Set Ready	8 + 6	20	Data Terminal Ready
Carrier Detect + Data Terminal Ready	1 + 4
Ground	5	7	Ground

Serial port to another serial port related links

- If your devices have other connectors (for example, DB-25 pin) look here: RS-232 - RS-232 connection using DB25 connectors.
- RS232 port connector with all pins.