How to Troubleshoot Keypad Loop on D4112 & D6112 Panel

Issue

How do I tell if my wiring is good and all the devices are connected on the D6112 keypad bus?

Solution

Remove the data wires from terminals 11 and 13 on the control panel. Also remove the power going to those devices. Using a multimeter set to read resistance, place one lead on a data wire and the other lead on the other data wire.

The correct resistance reading should be 9K Ohms per device connected.

Number of device / Device Resistance / Wire / Max resistance

1 9 k ohms 15 k ohms 23 k ohms

2 18 k ohms 15 k ohms 32 k ohms

3 27 k ohms 15 k ohms 41 k ohms

4 36 k ohms 15 k ohms 50 k ohms