Electrical systems. AV racks draw meaningful power and are sensitive to electrical problems that wouldn't bother a lamp. Dedicated circuits (a circuit not shared with other building loads) prevent AV gear from browning out when, say, an HVAC unit kicks on. Proper grounding prevents both safety hazards and a specific AV problem — ground loops, which show up as an audible hum in audio systems caused by a small voltage difference between two ground points. A UPS (uninterruptible power supply) protects against brief outages and gives equipment time for a clean shutdown, while power conditioners smooth out voltage fluctuations that would otherwise stress sensitive electronics.
This is also where the job posting's “manual labor” and “moving and lifting weights” requirements connect — technicians frequently work inside equipment racks and near live electrical panels, and basic electrical safety awareness (lockout/tagout concepts, not touching energized equipment, proper cable routing away from heat) is a baseline expectation even without being a licensed electrician.
Wireless radio systems. Wireless microphones operate in specific radio frequency bands (commonly VHF or UHF), and multiple wireless mics in the same room must be frequency-coordinated so they don't interfere with each other or with other RF sources in the building. Lectrosonics, named directly in the Newark posting, is a leading manufacturer of professional wireless microphone and IR (infrared) assistive-listening systems — the latter being especially relevant in a courtroom setting, where accessibility for hearing-impaired jurors, witnesses, or spectators is often a legal requirement, not just a convenience.
IR-based assistive listening is distinct from IR remote control (Week 5) — it uses infrared light to transmit an audio signal to a receiver worn by a listener, rather than transmitting short control commands to a device.