Whirlwind Qbox Audio Line Tester Portable Audio Line Tester and Signal Generator

The Qbox has been in service since 1997 and it is still the box people mean when they say they will go and check the line. It carries a microphone, a speaker, a test tone generator, a headphone output and a 1/4 inch jack for line in or a 2 kohm telephone earpiece, plus a clip for a belt or a rack rail.

Generate into or listen at any point from the microphone end to the amplifier end and you find out which section is working in one pass, without powering up the whole system. The tone generator runs at three levels for activating a signal path or picking one cable out of a pile of ends. Hook one Qbox up at each end of a line with headphones plugged in and you have an instant hands-free intercom, and LEDs confirm the presence of intercom or phantom power on a three-wire feed. It runs on a single 9 V alkaline battery in a rugged ABS shell.