Abstract: A system for transmitting and receiving both a slow scan television signal and a voice signal over a common communication channel is disclosed. The slow scan television signal includes horizontal sync pulses provided at a predetermined rate for defining a predetermined period. The horizontal sync pulse and video information for a video scan line are contained within a first portion of the predetermined duration.A multiplexing device alternately connects either a video transceiver or an audio transceiver to the communication channel. The multiplexing device connects the video transceiver to the communication channel during the duration of a first multiplexing control signal and during the duration of a second multiplexing control signal.The first multiplexing control signal is provided in response to the slow scan television signal provided by the video transceiver and has a duration corresponding to the first portion of the predetermined period.

Abstract: Apparatus for producing a video signal from digitally stored information representing the video signal intensity in each of a plurality of picture element locations within a plurality of scan lines. An analog video signal produced for display from the stored information is blanked during the first half of each picture element location during alternately displayed lines and blanked during the last half of each picture element location during the remaining alternately display lines. This apparatus is used in slow-scan television.