An infrared (IR) extension is a device capable of effectively increasing the range of an infrared signal. The two main types of extenders use either radio frequency (RF) waves or a physical cable to increase range. A radio frequency IR extension consists of an IR receiver coupled with an RF transmitter and an RF receiver with an IR transmitter. Other IR extension devices consist of an IR transmitter connected to a receiver by a physical cable. In both cases, the IR extension functions by converting a pulsed light signal into a different form and then back again.
Infrared light is commonly used to send control signals to consumer electronics such as audio receivers and televisions. Due to the attenuation of the light signal, and interference from other IR sources, these controls typically have a limited range. They also require line of sight to operate, so under normal circumstances it is impossible to control a device from another room with an IR remote. To work around these problems, devices known as IR extensions, extenders and repeaters are used.
One type of IR extension uses radio waves to improve the range of an infrared remote. This type of device is capable of receiving an IR signal, converting the information into a radio wave, and then sending it to a repeater box. The second box translates the information from the radio wave and then transmits an IR pulse identical to the original. These extension devices are limited in range as well, but sufficiently powerful transmitters can send a signal through walls, ceilings and floors into other rooms.
Another kind of IR repeater uses a physical connection to transmit a signal. Some of these devices have an IR receiver hardwired to an IR transmitter, though others use modular cables instead. In either case, the IR pulse from a remote is converted into an electric signal and sent over the wired connection. It is then translated back into an IR pulse and transmitted. This kind of IR extension will sometimes have a single receiver and multiple transmitters, each of which can be placed on a different device.
Some devices also have a jack that a type of IR extension can be plugged into. In most cases, this type of jack will make use of a tip ring sleeve (TRS) connection. The IR extension typically consists of a small IR receiver unit that is connected to a long wire and a TRS plug.