ARCHITECTS & ENGINEERS SPECIFICATIONS—PTL-1
The accessory shall be an end-of-line device for 70- and 100-volt distributed loudspeaker lines. It shall be used with DataPort-equipped or Q-Sys network-compatible power amplifiers that have output voltage and current sensing capability.
The device shall have two screw terminals in a ceramic block. Across these terminals the device shall present a series RLC circuit with an impedance null centered at 22 kHz. 
To aid verification of the distributed loudspeaker line’s integrity, the impedance shall be detectable by a Q-Sys network audio system that generates a 22 kHz pilot tone through the amplifier channel. The circuit shall have a fuse in series to protect the other components against excessive current.
The device shall be constructed upon an 84 × 84 mm (3.3 × 3.3 inch) printed circuit board and shall include an adapter plate to aid mounting in a typical electrical box.
The accessory shall be the QSC PTL-1 Pilot Tone Load.