The GS-1U028B unit is designed to provide a continuously repeated short message followed by line up tone to identify programme lines. Each channel can record up to 16 seconds of speech. If less than 16 seconds are recorded the remaining time is filled with line up tone at 1kHz. The recorded messages are stored in a non-volatile memory so are remembered even in the absence of power. An inbuilt microphone with compressor and limiter makes it very easy to record messages. Each channel has a front panel switch for record or playback. Output level is nominal zero level programme with the tone level set to 0dBu into a bridging load. Outputs on these 1U units appear on front panel bantam jacks in parallel with a rear panel varicon and are transformer coupled. A second varicon is provided to allow remote control of the record and playback functions. Provision is also made on the 1U units to use an external zero level recording source in addition to the front panel microphone.