Portable induction loop system

The Williams AV PLA 90 is a portable induction loop system designed for public accommodation at key customer and visitor points of contact. Its compact silver plastic enclosure combines an internal loop coil, microphone selection, battery operation, and universal AC power in a single unit weighing 1.4 lb with batteries. A specified 3–4 ft (1 meter) range focuses operation around a counter, desk, or similar close-contact position.

Ideal Use Cases

The PLA 90 is suited to locations where staff and visitors communicate at a defined point rather than across a large room. Its one-meter range aligns with teller positions, service desks, counters, and other customer or visitor contact areas. Because the system is portable, it can also accommodate locations where the intended contact point changes.

Measuring 7.9 inches high, 7.3 inches wide, and 2.9 inches deep, the unit can be positioned within limited counter or desktop space. Battery operation further supports flexible placement when continuous access to an AC outlet is not practical.

Why Choose This Model

The PLA 90 places its essential operating controls directly on the unit. It provides power-on and power-off control, rotary microphone gain for an external microphone, and a three-position selector for the internal microphone, an external microphone, or the internal and external microphones together. This selection makes it possible to configure the microphone path for the specific contact point.

A red flashing LED indicates that the battery is charging, a green LED identifies normal system operation, and an amber LED shows when audio input is being received. The internal microphone is specified at 60 dB sensitivity for full output. An external microphone can be connected through the 3.5 mm mono input, while a 3.5 mm stereo headphone output is also provided.

Installation and Integration

The compact PLA 90 is described as easy to install. Position the enclosure at the intended customer or visitor contact point, select the required microphone configuration, and adjust the external microphone gain when that input is used. The internal loop coil delivers up to 10W of loop output power within the specified operating range.

For powered operation, the supplied specification calls for a universal 100–240VAC, 50/60Hz input power supply with 16VDC, 1A center-positive output. The system can also operate from its 12VDC, 1300mA/h NiMH battery pack, which consists of ten AA cells. These two power options allow the system to serve either a consistent installation point or a location requiring portable operation.

Performance Highlights

• Specified operating range of 3–4 ft, or approximately 1 meter.
• Maximum loop output power of 10W through the internal loop coil.
• Internal microphone sensitivity of 60 dB for full output.
• Three microphone modes: internal, external, or internal plus external.
• Up to 6 hours of battery operation following a full 4-hour recharge.
• Automatic power-off after two minutes without audio from either microphone when operating only on battery power.

The automatic timeout helps manage battery operation when the system is left without an active audio signal. Its separate charging, operation, and audio-input indicators provide immediate confirmation of the unit’s current state.

What Makes It Different

The PLA 90 brings the loop coil, internal microphone, controls, rechargeable battery, and status indicators into one portable enclosure. The choice between internal and external microphones, including simultaneous internal-plus-external operation, provides more configuration flexibility than a single-input design. Its focused one-meter range is specifically aligned with direct customer and visitor interactions.

The system carries CE, RoHS, and WEEE approvals. Williams AV specifies a two-year parts-and-labor warranty for the system, with a 90-day warranty applying to most accessories.

Final Assessment

The Williams AV PLA 90 is a focused solution for establishing a portable induction loop at an individual point of contact. Its compact dimensions, 1.4 lb operating weight with batteries, six-hour battery life, universal power supply, selectable microphone paths, and clearly defined 3–4 ft range make its capabilities straightforward to evaluate. For counters and desks requiring a self-contained loop system with both portable and powered operation, the PLA 90 provides a clearly specified configuration.