Detecting an Open Collector on the AT1616

The hardware giving the open collector (the "external equipment") 
should have two terminals for this signal: the open collector and 
the ground (ground might be labeled 'common').

Choose the input on the AT1616. Remove the jumpers near those 
terminals, then place one jumper over the pair of pins furthest 
from the terminals. Wire the positive terminal to the +V terminal 
on the AT1616. Wire the negative terminal to the open collector. 
The table below shows the terminal pairs for each input channel:

                  Negative Terminal          Positive Terminal
    Channel      (to Open collector)          (to +V terminal)
    B1-A                2                             1
    B1-B                4                             3
    B1-C                6                             5
    B1-D                8                             7
    B1-E                9                             10
    B1-F                11                            12
    B1-G                13                            14
    B1-H                15                            16
    B1-P                18                            17
    B1-O                20                            19
    B1-N                22                            21
    B1-M                24                            23
    B1-L                25                            26
    B1-K                27                            28
    B1-J                29                            30
    B1-I                31                            32

Wire the ground on the external equipment to the COM terminal on 
the AT1616. [There are two locations of the +V and COM terminals 
on the AT1616. It does not matter which pair you use.]

To test to make sure the wiring is correct: disconnect the wires 
from the open collector and the ground, both on the external 
equipment, and touch the ends together. The green input LED will 
go on.