Perle Systems 1700 manual RS232 Null-Modem Cable Configuration, Figure D-9 RS232 Null-Modem Cable

RS232 Null-Modem Cable Configuration

DB25 MALE						DB25 MALE
	1	Shield		Shield	1
	2	Transmitted Data		Received Data	3
	3	Received Data		Transmitted Data	2
	4	Request To Send		Data Set Ready	6
	6	Data Set Ready		Request To Send	4
	20	DTE Ready	Received Line Signal Detector (CD)		8
	7	Signal Ground		Signal Ground	7
	8	Received Line Signal Detector (CD)		DTE Ready	20
	15	Transmit Timing DCE Source		Receiver Timing DCE Source 17
	17	Receiver Timing DCE Source		Transmit Timing DCE Source	15
	24	Transmit Timing DTE Source		Transmit Timing DTE Source	24

Figure D-9 RS232 Null-Modem Cable

The connecting cable must be a shielded cable.

This cable is needed when it is necessary to connect two units back-to-back and a set of modems is not available. Note that this cable specifies DB25 connectors on each end to allow direct connection to the link interface connector on each unit. The link speed must be defined for each of the two units.