Circuit Indicates That Voice-Recording Disks Are Nearly Full

A remote alarm circuit provides visible and audible signals to indicate that there is little unused space left on magnetic and optical tracks on disks used to record voice signals in a group of three multichannel voice recorders. In the particular application for which the remote alarm circuit was built, the voice recorders are required to operate without interruption, but the technicians responsible for the continuous operation of the voice recorders perform most of their duties on a different floor of the building in which the voice recorders are located. The remote alarm circuit gives sufficient advance warning to enable the technicians to go to the voice recorders and change recording disks in time to ensure continuity of recording.