Terminal equipment for telecommunications and information processing

摘要

Terminal equipment for telecommunications and information processing with improved electromagnetic compatibility (EMC). The equipment has a human-machine interface (HMI), a metallic telecommunications interface (TCI), and optionally a power line interface (PLI). First common-mode rejection filters consisting of common-mode choke coils and shunt capacitors are placed at the HMI interface of the equipment, while second common-mode rejection filters consisting of the same components are placed at the TCI and PLI interfaces. High-frequency junction points of the first and second common-mode rejection filters are interconnected with a bypass circuit. Being isolated from the signal ground and frame ground of the equipment, the bypass circuit is an independent non-grounded circuit. Such internal structure makes it possible to reject noise signals induced by an external noise source and also to suppress spurious radiation from an internal noise source.