Multitech MT5600BA, MT5600BL manual RS-232 Cable Pinouts, Appendix F - Pin Descriptions

			Appendix F - Pin Descriptions
Label	Pin	I/O type	Signal name/description
RDL	21	RDL	Remote Digital Loop Input to modem to enable RDL test.
RI	22		Ring Indicator RI output high indicates the presence of
			a ring signal on the telephone line.
	23		NC
XCLK	24	XCLK	External Clock Input to modem used in special
			synchronous applications.
TM	25	TM	Test Mode Output from modem to indicate modem is in
			one of the test modes.

RS-232 Cable Pinouts

DTE DB-25		DCE DB-25
connector		connector
TD	2		2	TD
RD	3		3	RD
RTS	4		4	RTS
CTS	5		5	CTS
DSR	6		6	DSR
GND 7			7 GND
CD	8		8	CD
DTR 20			20 DTR
RI 22			22	RI

Fig. F-1. 25-pin to 25-pin RS-232 cable.

DTE DB-9		DCE DB-25
connector		connector
TD	3		2	TD
RD	2		3	RD
RTS	7		4	RTS
CTS	8		5	CTS
DSR	6		6	DSR
GND 5			7 GND
CD	1		8	CD
DTR	4		20 DTR
RI	9		22	RI

Fig. F-2. 9-pin to 25-pin RS-232 cable.