Circuit arrangement for maintaining an emergency operation in a broadband transmission link

摘要

When the power supply fails, for example in a broadband connection, it should be possible to maintain an emergency operation over a relatively long time via assemblies fed by local batteries and a basic access multiplex channel should be available for voice and narrowband data at a reduced bit rate. The circuits needed for the highest frequencies (approx. 140 MHz) which have a high current consumption, are disabled when the power supply fails. A number of switching multiplexers are provided which are activated by an emergency signal which is generated when the power supply fails. The switch-over of the clock supply to a clock generator operating at a lower frequency and the switch-over of the datastream is thus effected in such a manner that the disabled circuits are bypassed or replaced. The circuit arrangement should be used in broadband data connections, existing circuit sections which have a low current consumption also being used in emergency operation so that this emergency operation can be maintained over a relatively long time, the additional expenditure for switch-over measures being extremely low.