Nullmodem 9 to 25 Pin Cable Pinout - AllPinouts
Use this cable between two DTE devices (for instance two computers).
|D-Sub 9||D-Sub 25|
|Receive Data||2||2||Transmit Data|
|Transmit Data||3||3||Receive Data|
|Data Terminal Ready||4||6+8||Data Set Ready + Carrier Detect|
|System Ground||5||7||System Ground|
|Data Set Ready + Carrier Detect||6+1||20||Data Terminal Ready|
|Request to Send||7||5||Clear to Send|
|Clear to Send||8||4||Request to Send|
- DSR & CD are jumpered to fool the programs to think that they are online.