In a digital dictation and transcription network of the type having a plurality of dictation stations and a plurality of transcription stations, a modular digital dictation system, including:
- a line interface card connected to said dictation stations, said line interface card receiving from said dictation stations digitized dictation signals representing modulated voice signals to be transcribed, and said line interface card transferring said digitized dictation signals received from said dictation stations onto a time division multiplexed data bus;
- a signal processing card connected to said line interface card and receiving said digitized dictation signals output from said line interface card, said signal processing card compressing said digitized dictation signals;
- a timing card connected to said time division multiplexed data bus for detecting said signal processing card and said line interface card, and for initializing a variable number of signal processing cards and line interface cards;
- a controller for receiving said digitized dictation signals output from said signal processing card, and for controlling the transfer of said digitized dictation signals between said signal processing card and a memory storage device;
- and
- a power supply connected to said modular digital dictation system, said power supply comprising of plurality of energy sources configured to continuously supply power to said modular digital dictation system and a redundancy circuit that tests each energy source and outputs a service request signal if an output of one of the energy sources does not meet an appropriate voltage level.