3 Relay Out 2 16 Relay Out 2
4 Relay Out 1 17 Relay Out 1
5 IN + opto 4 18 IN - opto 4
6 IN + opto 3 19 IN - opto 3
7 IN + opto 2 20 IN - opto 2
8 IN + opto 1 21 IN - opto 1
9 I/O TTL 8 22 GND (Return I/O 8)
10 I/O TTL 7 23 GND (Return I/O 7)
11 I/O TTL 6 24 GND (Return I/O 6)
12 I/O TTL 5 25 GND (Return I/O 5)
13 + 5V 50mA max.