You asking about the remote temperature probe? Used with the 2441ZTH Insteon Wireless Thermostat or a remote thermostat sensor that can be wired into a 2441T thermostat. The 2441T does not have any terminals for a remote sensor.
The older 2491T1E and 2491T7E built on a Venstar T1700 or T1800 should have had the terminals but I am not sure if they where active as they where custom assemblies with an added daughter board installed. To Smarthomes specification.