This base transmitter is part of the Telex SoundMate personal listening system used by the hearing-impaired in hotels, churches, and exhibit booths to overcome background noise and poor building acoustics that make listening difficult.

It features 17 user-selectable frequencies digitally controlled from the front panel control buttons, a headphone jack with adjustable level for input signal monitoring, and a backlit LCD display that shows Channel, Frequency and Audio Input Level. On the back of the unit is a balanced XLR-3F as well as an unbalanced 1/4” input. Front panel controls and LCD display allow the user to select mic, line, and 70 volt input options, attenuate the input levels and change hi/low RF transmit power. A new feature called Enhanced Dynamic Range (E.D.R.) works with the SR-400 receiver to provide clearer, more dynamic audio.