Technology

IR

IR stands for Infra Red transmissions which are commands embedded in a light wave. The light is at a wavelength invisible to the human eye, primary limitation is that it's based on line of sight as such solid objects will block the signal, therefore the remote must be pointed at the receiver (TV, VCR IR port) in order for the command signal to be successfully transmitted.

RF

RF stands for Radio Frequency transmission. This is where the command is embedded in a radio signal in a similar method to Radio or TV broadcasts. It is not limited to line of sight and possible to transmit through brick walls. The primary advantage is that line of sight is not important, this can be beneficial in entertainment installations where the hardware is in enclosed in an ergonomic cabinet for aesthetic reasons.

Universal Remote

A universal remote is a remote control that can be programmed to operate various brands of one or more types of consumer electronics products. Entry level universal remotes can only control a set number of devices determined by their manufacturer, while mid- and high-end universal remotes allow the user to program in additional control codes to the remote, these types offer the most flexibility.

Bluetooth

Bluetooth is an alternative RF standard as integrated into Mobile Phones. With Bluetooth it would be possible to control consumer electronics however the has limited appeal compared to full Universal Remotes.

Wi-Fi

An alternative RF standard as integrated into Wi-Fi Networks, with Wi-Fi it would be possible to control consumer electronics however it has limited appeal compared to the traditional RF Universal Remotes.

Touch Screen (LCD)

A touch screen can be Monochrome or Colour. It is an alternative touch input method used on advanced remotes, mostly limited to the Macro keys that are used to send a series of commands in sequence. These Macros would be represented by a meaningful Icon such as a TV.