Arrows show direction
of signal to & from a DTE
( > source is DTE ) ( < source is DCE )
DB25
1 --- Ground
2 --- TX >
3 --- RX <
4 --- RTS >
5 --- CTS <
6 --- DSR <
7 --- COM
8 --- DCD <
9 --- + Volts
10 --- - Volts
15 --- TX CLOCK <
17 --- RX CLOCK <
18 --- LL
20 --- DTR >
21 --- RL
22 --- RI <
24 --- Ext Tx Clock >
25 --- Test Mode
DB9
1 --- DCD <
2 --- RX <
3 --- TX >
4 --- DTR >
5 --- GROUND
6 --- DSR <
7 --- RTS >
8 --- CTS <
9 --- RI <
1 ----- 8
2 ----- 3
3 ----- 2
4 ----- 20
5 ----- 7
6 ----- 6
7 ----- 4
8 ----- 5
9 ----- 22
UTP (568B)
1 --- W/OR
2 --- OR/W
3 --- W/GRN
4 --- BLUE/W
5 --- W/BLUE
6 --- GRN/W
7 --- W/BRN
8 --- BRN/W
CROSSOVER
1 --- 3
2 --- 6
3 --- 1
6 --- 2