* Split Design = One‑Person, Two‑End Troubleshooting: AT‑3 includes AT‑3M (send/generate) and AT‑3F (receive/monitor), so you can test a long run without running back and forth. Built for live sound, church audio, DJs, rentals, and touring rigs. * Built‑In Signal Generator: Send a known-good test signal to verify mixers, active PA speakers, DI boxes, pedals/effects, wireless/IEM systems. Choose 1kHz sine or pink noise with 3 output levels (-40 / -20 / -10 dBu) for easy input matching. * Long‑Distance Cable Testing for XLR / DMX Runs: Place one unit on each end for fast end‑to‑end checks and pin fault diagnosis on long cables. Multiple cable test modes (auto + manual pin selection) help you find issues quickly—especially intermittent stage lines. *48V Phantom Power Check (Pins 2 & 3) + XLR Input Meter LEDs: Verify phantom power voltage at a glance (solid: 44–52V; flashing: 24–44V) and confirm signal presence with SG/PK metering—perfect when the venue is too loud to rely on your ears. * Monitor Anywhere: AT‑3F lets you listen via 1/8" headphones or the built‑in speaker (speaker auto‑mutes when headphones are plugged in). USB‑C charging (5V/2A), ~1.5 hr full charge, low‑battery warning, plus magnetic mount for convenient placement.