We have a Qty of these super clean JPS Interop / Communications (Formerly Raytheon).  Each Chassis is in excellent, known working condition, and configured the same:
A typical SNV-12 Signal-and-Noise Voter application is an LMR system in which mobiles and portables can hear a repeater, but the repeater can’t hear them, due to their lower transmit power and/or the antenna size or placement. Remote receivers can be positioned in the communications dead spots, with audio from each receiver linked to the voter via IP or T1 microwave, IP fiber, landline, twisted pair, RF link, or fiber optics. The voter will select the best quality signal from all unsquelched remote receivers and forward this signal to the repeater for rebroadcast or monitor by a dispatcher, thus providing greater talk back range for the radios.