Mid-range Infrared Transmitter

Product Highlights

  • Designed to maximize coverage area up to 5,000 sq. ft.
  • Meets ADA accessibility guidelines
  • Looks great! Sleek, professional styling complements room aesthetics.
  • Front cover can be painted to match décor.
  • 2 year Warranty


The WIR TX75 infrared transmitter ensures participants in your conference room, courtroom, classroom or other mid-sized venue receive direct, clear communication of your message without sacrificing security. The sleek and stylish TX75 is designed to maximize coverage area up to 5,000 square feet in single-channel mode when using the RX22-4 receiver. Two slaves (WIR TX75-S) can be added for additional coverage up to 5,000 square feet each (15,000 sq. ft. total), when mounted up to 100 feet from the master transmitter. Placing additional slaves in the same room increases coverage and enhances freedom of movement. A single CAT-5 cable carries both power and signal to slaves–truly a one-cable connection. Operates on the 2.3 / 2.8 MHz bandwidth. Mounting bracket and international power supply are included.

System Includes

(1) WIR TX75 infrared transmitter

(1) BKT 024 wall / ceiling mounting bracket

(1) TFP 046 international power supply with WLC 004 U.S. mains AC plug


  • Green power – if no audio is present after a few minutes, unit automatically disables power to IR diodes, reducing power consumption by 80 percent.
  • TX75-S slave emitter available for use with TX75 (sold separately)
  • Headset, stethoset and body-pack receivers available for use with TX75 (sold separately).
  • Robust digital communication bus between master and slave units reduces interference.
  • Master unit has troubleshooting lights built in to simplify installation.
  • Separate RCA audio inputs for each channel (2.3/2.8 MHz) accept balanced or unbalanced line level inputs; use together for stereo operation or separately for mono.
  • Unit senses if only one channel is in use and doubles the output power on that channel for twice the coverage.


WIR TX75 Architectural and Engineering Specifications

  • The Infrared Transmitter shall consist of an all in one modulator and emitter operating on 2.3MHz and/or 2.8MHz. The carrier frequency shall use 50kHz deviation and 50µS pre-emphasis.
  • The Transmitter shall have a minimum coverage of 5,000 sq ft with the WIR RX22-4 receiver in single-channel mode.
  • The Transmitter shall be housed in a heavy-duty black plastic enclosure with a durable infra-red transparent front lens. It shall be convection cooled without fans. The Transmitter includes an omni-directional mounting bracket for various permanent installations.
  • The Transmitter shall have a line level RCA input for each of the channels. Each channel shall have an audio input level LED. There shall be a single 3.5mm microphone input with gain control. The mic input shall have a channel selector switch.
  • The Transmitter shall have a switch to turn off all indicator LED’s. There shall be a switch for selecting either balanced or unbalanced line level inputs.
  • The Transmitter shall have two RJ45 outputs supplying power and baseband signal to two WIR TX75-S slave emitters via CAT-5e cable. Each RJ45 output shall have a green and yellow LED signaling that the slave emitters are receiving power and baseband signal. A single CAT-5e cable supplies power, signal and digital control to the slave unit up to 100 ft from the Transmitter.
  • The Transmitter shall be powered by a 48VDC universal power supply, 50-60Hz, 100-240 VAC input, 19.2W.
  • The Transmitter shall be covered by a two-year parts and labor warranty, 90 days on accessories.
  • This Transmitter shall be the Williams Sound model WIR TX75.


Dimensions, Weight:

10.0" W (25.4 cm) x 3.1" D (7.9 cm) x 1.5" H (3.8 cm) w/o faceplate or 2.5" H (6.4 cm) w/faceplate, 0.6 lbs (0.3kg)


Black with silver colored silk screen and silver colored faceplate

Optional: white colored faceplate

Power Supply:

Desktop style international power supply with IEC line cord, 100-240 VAC input, 50-60Hz, 24W; 48VDC output

DC Power Input:

2.5mm ID barrel connector, 48 VDC, 0.4A center positive

Power Indicator:

Green LED

Sleep/Power Save Mode:

Shuts off carrier when no audio is present for 3 minutes


FM Wideband, ±50kHz deviation max, 50 μS pre-emphasis

Carrier Frequencies:

 2.3 MHz (Ch1) and 2.8 MHz (Ch2)

Default at power on = carriers off. Carriers are automatically enabled upon presence of audio.

Emitter IR Power:

0.7 W

Master Only Coverage Area
(minimum, 1-Ch mode):

5,000 sq. ft in single-channel mode with the RX22-4 receiver (464 sq. m)

3,000 sq. ft in single-channel mode with the RX15-2 receiver (279 sq. m)

2,000 sq. ft in single-channel mode with the RX18 receiver (186 sq. m)

Audio Inputs / Controls:

Line inputs: RCA jack for Ch1 and Ch2 accept line level, balanced or unbalanced audio

Line in balanced/unbalanced switch: selects balanced or unbalanced line level audio for RCA jacks

Microphone input:

3.5 mm, stereo jack with signal and bias connected to tip, electret microphone compatible (4 VDC bias supply with 2.7k ohm series resistor)

Microphone gain adjust:

Rotary potentiometer

Microphone channel switch:

Selects microphone input to Ch1 or Ch2

Audio indicators:

Yellow LED blinks at nominal audio level. One per channel

Indicators On/Off:

2-position switch turns on/off indicator lights

“to slave" Output/Input:

(2) 8p8c RJ45 connectors output 48VDC 0.4A power, baseband RF and a bi-directional RS-485 bus for control and status communications

Slave Status Indicators
(on “to slave" jacks):

Green: Power/Unit Status

Yellow: Transmit/Cable Status

Signal-to-Noise Ratio:

70 dB, (line input)

Frequency Response:

95Hz to 17.6kHz, -3dB re 1kHz (line inputs)

125Hz to 17.0KHz, -3dB re 1kHz (microphone input)

Total Harmonic Distortion:

<1% (1 kHz, nominal deviation, line or microphone input)

Operating Requirements:

0-50° C (32°-122°F)

Mounting Kit:

Wall or Ceiling mount: BKT 024 Omnidirectional mount

Optional: slave linking bar (MLB 003)


2 Years


CE, C-tick, FCC, Industry Canada, WEEE, RoHS, CB Scheme

Compatible Receivers:

WIR RX22-4, WIR RX18, WIR RX15-2

Accessories for WIR TX75 IR Transmitter

BKT 024 Wall/ceiling mounting bracket

MLB 003 Linking Bar for WIR TX75

Products compatible with WIR TX75 IR Transmitter


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Download/View Name Type Language
Building Information Modeling (BIM) CAD Drawings English
IR for Ease EASE English
DC6 - Powering TX75 VIA CAT5.pdf CAD Drawings English
WIR TX75 Sell Sheet Sell Sheets English
WIR TX75 Sell Sheet Español Sell Sheets Español
Design Guide - Designing IR Systems for Air Walls Design Guides English
Infrared Brochure - Low Res Brochures English
WIR TX75 Manual Manuals English
WIR TX75 Quick Setup Guide Manuals English
White Paper - Powering the TX 75 with PoE White Papers English


Name Description Duration
Williams Sound: WIR TX75 Preview

Preview of the Williams Sound WIR TX75