Apparatus for lightning strike survivability and post-strike operability

摘要

A communication system (10) includes a central office (16) that provides communication services to a plurality of subscribers (18) using differential transmission line pairs (21). The differential transmission line pairs are vulnerable to lightning strikes that may damage equipment coupled to the differential transmission line pairs. A protection circuit (51A) protects equipment from damage from a lightning strike and allows for continued operation after the lightning strike. The protection circuit involves automatically resettable fuses (66, 81) in parallel with non-resettable fuses (67, 82). Continued operation is effected at a normal level after a weak lightning strike, and at a reduced level after a strong strike.