EV, You are correct about those ring tranfer switches causing diode matrix ringing nightmares . If not properly installed key phones that did not share the same key lines but had a transfer switch connected to the bell in thier phone would cause the bell to ring but no key lines would light up and flash . One of the early causes of phantom ringing on key sets . Also why did some companys take the hundred pair cable on the 1a2 call commander phones and break them out into 5 amphenol connectors ? There must of been a reason !
