RS-232		
25 PIN	9 PIN		

1		FG	FRAME GROUND
2	3	TD	TRANSMIT DATA
3	2	RD	RECEIVE DATA
4	7	RTS	REQ TO SEND
5	8	CTS	CLEAR TO SEND
6	6	DSR	DATA SET READY
7	5	SG	SIGNAL GROUND
8	1	DCD	DATA CARRIER READY
9		+V	POS TEST VOLTAGE
10		-V	NEG TEST VOLTAGE
11		QM	EQUALIZER MODE
12		DCD2	2ND DCD
13		CTS2	2ND CTS
14		TD2	2ND TD
15		TC	TRANSMITTER CLOCK
16		SRD	2ND RD
17		RC	RECEIVER CLOCK
18			
19		RTS2	2ND RTS
20	4	DTR	DATA TERMINAL READY
21		SQ	SIGNAL QUALITY DETECT
22	9	RI	RING INDICATOR
23			
24		TC	EXT TC
25				
				


 Standard Cable....everything straight through

 Simple dumb cable...pins  2,3,7...straight through


 Null Modem Cable Pinouts 
 

1 -------- 1

2 -------- 3	2 -------- 3

3 -------- 2	3 -------- 2

4 -------- 5	7----------8

5 -------- 4	8----------7

7 -------- 7	5----------5

6 -----|	6----|
       |-- 20	     |-----4
8 -----|	1----|

      |---- 6	     |-----6
20----|		4----|
      |---- 8	     |-----1