System and method for telephone network testing

DETAILED DESCRIPTION To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention in accordance with the principles set forth herein, discloses a system and method for telephone network testing wherein complete duplex diagnostic testing is performed.
The system comprises a maintenance termination unit, a half-ringer having an AC impedance suitable for ringing current testing, and an identification response unit for verifying the identity of the subscriber loop.
The method for telephone network testing includes ringing current testing, fault identification and location, transmissions measurements, noise measurements, and subscriber loop identification, all remotely accomplished from the local central office.
In one aspect of the present invention, means for providing an AC signature enable presently available ringing current tests to be utilized.
This aspect of the present invention provides an impedance which produces a ringing current of known characteristics.
Current flows back to the central office and is compared to a template of expected current for testing the continuity of the subscriber loop up to and including the demarcation point between the telephone network and the inside wiring of the subscriber.
In another aspect of the present invention, means for isolating the telephone network from the internal wiring of the subscriber loop are provided without effecting normal subscriber service.
This aspect provides isolation between the network and subscriber when the service is inactive.
An off-hook condition causes the isolation to break down and bridge the customer's inside wiring to the network providing transparent service between the central office and the customer.
Without effecting normal subscriber service, the central office may also impress a voltage of preselect value across the tip and ring pair to breakdown the isolation and access a DC signature between the tip and ring terminals