The WLIs are flush-mounted wall-mount line input units that can be integrated into various types of installation materials for system integration. They are equipped with two RCA (stereo) connectors on the front and a terminal block connector on the rear.

The signal applied to the input connections is converted into a differential dual-mono signal with increased voltage levels. This makes the signal insensitive to interference and noise and can be transmitted over long distances without loss of quality. This enables reliable signal transmission up to 300 meters via CAT5E (or better) twisted-pair cabling. It must be used in combination with a corresponding device at the receiver end.