To integrate your existing ButterflyMX video intercom system with Openpath, connect a dry contact relay from each intercom touchscreen to a REX input on the Openpath ACU. Twisted pair wiring is recommended. For new installations, note that 18 AWG wire is recommended for ButterflyMX power connections.

Additionally, you can wire a REX sensor in parallel with the intercom (figure 1) or directly to your locking hardware (figure 2), depending on the door location and building code requirements. 

Figure 1: Wiring ButterflyMX with optional in-parallel REX to 4-Door Controller

Figure 2: Wiring ButterflyMX with optional in-parallel REX to 4-Port Board

Figure 3: Wiring ButterflyMX with optional REX to mag lock on 4-Door Controller

Figure 4: Wiring ButterflyMX with optional REX to mag lock on 4-Port Board

Note on using ButterflyMX for access:

If you plan on using the ButterflyMX Card Reader for access (without an Openpath Smart Reader), run the W0, W1 and GND signals from the ButterflyMX to a Wiegand input on the 4-Door Controller or any I/O pair on the 4-Port, 8-Port, or 16 I/O Elevator Board. The ButterflyMX power supply and the ACU power supply should share a common ground. See How to wire Wiegand devices to Core Series hardware.

If you are installing an Openpath Smart Reader at the same entry as the ButterflyMX, connect the Wiegand W0 and W1 signals from the ButterflyMX directly to the WD0 (Green) and WD1 (White) wires on the Smart Reader pigtail.

The REX signal can also pass back to the ACU in the same cable bundle as the Smart Reader wires if there is a spare twisted pair available. Run power for the ButterflyMX separately, since it requires heavier gauge wires.