TV listening devices allow individuals to adjust the volume of the TV according to their needs without making it too loud for others. The main components of a TV listening device include a transmitter and receiver. The transmitter interfaces with the TV (or other audio device) and serves as the charging unit for the TV listening system’s headset. In addition, the
transmitter is designed to wirelessly send the audio output of the TV to the receiver worn by the user, usually in the form of an under-the-chin headset. The signal delivered by the transmitter to the receiver will be one of the following: 1) an infrared (IR) signal or 2) a radio frequency (RF) signal.
Infrared (IR) devices are designed such that the transmitter sends signals from the TV to the receiver via an invisible beam of light. The user is able to manipulate the volume of the incoming signal utilizing the volume control of their under-the-chin headset. Since this technology relies on the use of light transmission, IR devices require the user to maintain a reasonable line-of-sight between the transmitter and receiver for efficient and uninterrupted signal transmission. For example, if the user of an IR device leaves the room while wearing the headset, transmission of the TV signal will quickly be lost, resulting in static. Other sources of potential interference include flourescent lighting and sunlight. Most IR systems are not compatible with plasma TVs. One advantage of IR devices is the headset may potentially be used outside of the home in other venues (i.e. theater, symphony hall, etc.) equipped with compatible and functioning IR transmitters.
Radio frequency (RF) devices function in the same fashion as IR devices with the exception that the transmitter sends signals from the TV to the receiver via a radio frequency or RF signal. The main advantage of this transmission technology is the absence of line-of-sight restrictions; the user of an RF device can leave the room or the house without losing signal transmission assuming the user remains within established system operating distances.