Null modem cable (DB9-DB9). Pinout and signals for building a serial (RS232) nullmodem cable

Use this cable between two DTE (Data Terminal Equipment) devices (for instance two computers).

	DB9 pin D-SUB female to PC1
	DB9 pin D-SUB female to PC2

	DB9-1	DB-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 fool the programs to think that they are online.

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