Serial Port to Serial Port connections. Cable wiring and pinout

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

RS232 port pinout (D-SUB female) on Side 1 RS232 port pinout on Side 1
RS232 port pinout (D-SUB female) on Side 2 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
Note: DSR & CD are jumpered to show the rs232 software or rs232 devices that another side is online.

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
Download Our RS232 Software Bundle
Our software allows you monitor, log, debug and test any your RS232 or COM ports.

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.