Clear-Com HX System Frames - Manual (Page 47)

Non-isolated mode
Note:
The non-isolated mode is the default mode, when the matrix frame leaves the factory.
Figure 14: Non-isolated connection to Eclipse GPI connector
To cause an input to detect an active signal, current must flow from the relevant input pin.
The external device should draw no current to cause an inactive input and at least 5 mA to
cause an active input. The opto-isolator drive line contains a 1.5 kOhm resistor to limit the
current through the opto-isolator. Therefore the input pins can be connected directly to a
ground pin to cause an active input.
The voltage level at the external input pin should not be allowed to go below ground or
above +6 with respect to ground.
Note:
The Logic 1 input (external input 1) must be shorted to ground to render the Logic 1 signal
active.
47 Eclipse HX Matrix Frame Installation Guide