The Contacta STS-A31H is the standard open-duplex amplifier that ships with most Contacta window intercom kits, and it is available as a standalone unit for installers building custom systems or replacing a failed amplifier in an existing Contacta installation. Open-duplex operation lets both parties speak at the same time without the clipped, walkie-talkie feel of half-duplex systems, and constant-current hearing loop drive with an engineer-adjustable level lets the amplifier drive an IL-AE98 or IL-AE99 hearing loop aerial so customers with hearing aids in the T-coil position pick up the audio directly. The STS-A31H is compatible with all Contacta window intercom customer-side and staff-side hardware, plus the PS-55 power supply.

The amplifier's energy-saving green standby mode is engaged automatically, cutting power draw by up to 80% during periods with no active speech. A green and red LED column indicates power and status and helps installers calibrate levels during setup. Continuous self-testing means no specialized equipment is required to confirm functionality after installation, and an isolated audio line input or output can be specified (as a custom option, not available together) for interfacing the amplifier with a recording system.

The STS-A31H housing measures 1.57 inches tall, 4.53 inches wide, and 4.57 inches deep in matte black ABS plastic with a fine textured finish, so it mounts discreetly under a counter or inside a service cabinet. It runs on 12 to 14 volts DC through a 2.1 mm DC jack, drawing 100 mA typical in standby and 2 amps typical on speech peaks. The system is CE, RoHS, and WEEE compliant.

If you're not sure whether the STS-A31H is the right replacement or upgrade for your installation, please call us at 800-207-2259.

Features:

• Open-duplex communication (both parties can speak simultaneously)
• Compatible with all Contacta window intercom customer-side and staff-side hardware, plus the PS-55 power supply
• Energy-saving green standby mode with up to 80% power saving
• Constant-current hearing loop drive with engineer-adjustable drive level (drives IL-AE98 or IL-AE99 hearing loop aerials)
• Isolated audio line input or output for interfacing to a recording system (custom, not available together)
• Green and red LED column for power and status indication and level calibration
• Continuous self-testing (no specialized equipment required to confirm functionality)
• Push on / push off power switch (tact switch under membrane)

Standards and Compliance:

• CE compliant
• RoHS compliant
• WEEE compliant

Physical Data:

• Dimensions: 1.57" H x 4.53" W x 4.57" D
• Weight: 0.22 lb
• Construction: ABS plastic housing
• Finish: matte black, fine texture

Technical Data:

• Supply voltage: 12-14 VDC via 2.1 mm DC jack
• Quiescent current: 100 mA typical
• Operating current: 2 A typical on speech peaks
• Microphones: electret, 5V supply via 2.2K load resistor
• Speaker output power: 2.5W RMS at 8 ohm / 4.4W RMS at 4 ohm
• Hearing loop drive compliance: constant current, bounded by 4V RMS and 2A RMS
• Total harmonic distortion: less than 5% (loop and speakers)