The REFUM belt-pack referee system offers sports officials the latest digital/analog hybrid technology in a convenient, weather-resistant package. Using the REFSWITCH external belt-pack switch assembly, the audio in the REFUM transmitter can be muted or engaged, without pops or clicks in the audio. A 5-pin input jack provides taps for low impedance dynamic mics, electret lavalier mics (positive or negative bias) and a pin designated for audio muting using an external switch. Input gain is adjustable over a 43 dB range to perfectly match the audio input level for optimum modulation, minimum distortion and maximum signal to noise ratio. Input levels are accurately indicated by two LEDs on the control panel.

The REFUM operates with all Lectrosonics Digital Hybrid Wireless™ receivers and a variety of analog receivers. The input is gain controlled with a wide range dual envelope input limiter, which cleanly limits input signal peaks over 30 dB above full modulation. Along with the Digital Hybrid Wireless™ audio path, the RF transmission is an aggressively optimized FM system with +/- 75 kHz wide deviation for a high signal to noise ratio. The overall system delivers full bandwidth audio frequency response up to 20 kHz plus excellent operating range and resistance to interference.

The REFUM is powered by a single 9 V battery and provides a full 100 mW output for extended operating range. The housing and belt-clip are machined aluminum, powder coated and laser engraved for ruggedness and legibility.