Each Zone on the panel that is configured for BiWire mode must have the intelligent end of line module (EOLM-3) fitted to continually monitor each zone for the presence of fault conditions such as detector head removal, open or short circuit and for end of line failures even when in a Fire condition.
 
For new installations, any Zone on the panel that is configured for Conventional mode can use the intelligent end of line module (EOLM-3) to terminate the zone but the panel will be limited to only detecting the presence of open or short circuit conditions to make it backward compatible with the EOLM-1. All detector head removals will be seen as an open circuit condition. The EOLM-3 module can be placed into the base of the last manual call point or detector base.