Subscriber interface box
Subscriber line impedance measurement device and method
Subscriber line impedance measurement method and measuring circu
Subscriber line maintenance apparatus and methods
Subscriber line monitoring circuit
Subscriber line test system
Subscriber line test system for access network
Subscriber line tester
Subscriber line validation of a telephone network
Subscriber loop tester for telephone switching systems
Subscriber system testing method
Subscriber telephone equipment test apparatus
Subscriber terminal circuit for connecting an analog subscriber
Subscriber testing system
Subscriber's line testing apparatus
Subscriber/craftsperson ringback apparatus
Switch testing
Switch-adjunct interface
Switch-adjunct interface
Switch-based line continuity verification method and system