TrueAlarm Sensing and IDNet communication isolation. The 4098-9793 IDNet Communications Isolator Base provides Simplex TrueAlarm analog sensor operation and also provides IDNet communications isolation to improve installation convenience and increase system integrity. Isolation is automatically activated at the base when an output short circuit is detected and isolation can also be selected per base manually from the control panel to assist with troubleshooting wiring problems. Operation. Isolator bases power-up in isolation mode and are directed to connect by the control panel. If the output wiring is acceptable, the isolator base will connect to the rest of the circuit. If the output wiring is shorted, the isolator remains isolated. Status Tracking. The isolator reports back to the panel when it is in isolator mode and the extent of shorted wiring is reported back to the panel by identifying device addresses that are not communicating. [Isolators are assigned sequentially to low number addresses to expedite Signaling Line Circuit (SLC) power-up.