Null Modem Adapter DB25 Female to DB25 Female. Full handshake Null Modem. Most popular use is to connect two PCS together for data transfer.

NC= Not Connected
Pin		Pin
Shield	Shield
1		1
2		3
3		2
4		5
5		4
6		20
7		7
8		20
9		NC
10		NC
11		NC
12		NC
13		NC
14		NC
15		NC
16		NC
17		NC
18		NC
19		NC
20		6,8
21		NC
22		NC
23		NC
24		NC
25		NC