The Aprilaire 8811 Protocol Adaptor converts the Aprilaire 8870 Thermostats built in RS485 Communication to RS-232 Communication for use with Controllers such as the Elk M1 Gold Automation and Security Control Panel as well as other Automation Contollers. Requires 7.5 VAC input via the supplied transformer.

We also recommend an Aprilaire Model 8818 Distribution Panel when connecting more than one model 8870 thermostat.