I am trying to connect a GE zoneline 2100 (manufactured 6/97) to a wall thermostat (GE RAK 147D1) I am reading conflicting literature on what I need to complete the conection. The installation manual says I need the optional interface module (RAK OIM), but later it says that the unit comes equipped with everything I need to hook it up to a wall thermostat. The wiring diagram reinforces this to show the thermostat connecting directly to the connectors on the unit. Anyone have any experience with connecting a Zoneline (especially on a older model) to a thermostat? Much thanks in advance.