How do isolation transformers function for special protection service?
Unlike neutralizing transformers, isolation transformers are connected across the telecom pairs instead of being placed in series with the pair. As a result the isolation transformer will pass ac signals because of the changing magnetic field, but will not pass dc like the neutralizing transformer. Therefore when only isolation is used for special protection interface, other options or modifications must be made if dc signals are required to be passed to terminal equipment. 8. Other than electromagnetic devices, what other means are available to protect metallic telecom pairs and equipment from the stress of GPR and fault current induction? The surest means of protection is the separation of equipment on the ground grid from metallic telecom pairs by means of fiber optic isolator devices. This form of isolation requires the use of electronic circuitry at the interface of electrical signals and optical generated signals. Typically this is accomplished on printed circuit cards. Four to s
