I'm an HVAC guy that works with Crestron controlled systems. I was wondering how the remote 2 wire sensors like CHV RTHS communicate with a CHV thermostat. All the other manufacturer brands typically have 4 wires. 2 wires for power and 2 for data.

I am accustomed to remote temperature sensors (not humidity)that use 2 wires but that is simple RTD circuit.

I can't find any details in Crestron install manuals or their web site. Hoping someone can enlighten me.

Thanks,

It sends back digital info to the Creston thermostat and not analog.

Charris is right, but if 4 wire connections work better for you, you could use this  it works quite well and really can save your skin when you need to add a sensor and did not work it in to the origional design, or need to run one outside for advanced HVAC integrations (think motorized windows)...but it is still digital, (RS-485 bus to be specific, and proprietary to Crestron).