our hallway has 3 lights connected to 5 switches, where one was a time delay switch. All lights switches are connected by 2 wires. when the time delay switch started to fail, we try to replace it. we took off the time delay switch it had 4 connections (see diagram) Live In, Neutral In, Live out and "TRIG". was not able to find any info on the trig connection. New light switch had 3 connections (minus a trig connection). I did not connect the precious trig wire - the new light switches the lights on and off, but none of the other 4 switches work for either on or off - effectively only one switch works now. Not sure of purpose of trig connection or if possible to use existing wiring for a new switch.