| 摘要 |
<p>A novel logging system employing MÄN + 1Ü redundancy is disclosed having applications in recording both voice and facsimile transactions. The logging system includes M chains of N + 1 loggers. Each N + 1 chain includes N working loggers and a single spare logger. Within each chain. each working logger is coupled to a switch unit. Each switch unit is coupled between a group of input telephone lines and one working logger. The switch units are coupled to each other in a serial daisy chain fashion. The switch furthest downstream is coupled to a spare logger which is activated in the event one the working loggers fails. The switches include watchdog circuitry to detect the failure of a working logger. Once detected, the telephone lines coupled to the failed logger are rerouted to the spare logger. The system can support any number of working loggers by sectioning the working loggers into separate chains. Each chain includes a group of N working loggers covered by a single spare logger. The working loggers and the spare logger are managed by a controller which is coupled thereto via a local area network (LAN). The switch includes a plurality of 2 X 2 crossover switches which perform the actual switching function in the event a failure is detected in one of the working loggers. Each input telephone line is associated with one 2 X 2 crossover switch. <IMAGE></p> |
