test for faults in such a system or otherwise remotely control a repeater it is necessary to obtain access to each repeater by means of an addressing signal transmitted along the wavepath the present invention relates specifically to a verification scheme to confirm that the addressed repeater has in fact been accessed this is accomplished by means of a loop back arrangement employing the count down technique disclosed by j a bellisio in the copending application ser no 929 431 filed july 31 1978 and assigned to applicant 39 s assignee this addressing scheme involves transmitting a series of m recognizable signal bursts where m is an integer identifying the repeater to be addressed and is equal to the number of addressable repeaters between the addressing station and the addressed repeater inclusive each addressable repeater is designed to eliminate one of the signal bursts and to transmit the remaining bursts each repeater is also designed to respond in a prescribed manner when one and only one burst is received thus by means of this 34 count down 34 technique the m th repeater in the sequence of addressable repeater is accessed by the transmission of m signal bursts to provide verification one of the prescribed responses of.