IrDA, short for Infrared Data Association, is one of the three main methods used for wireless printing. IrDA devices communicate with each other by detecting pulses of light from the infrared spectrum. Communication between devices relies on a transceiver—a transmitter plus a receiver—to transmit and receive the infrared rays. The devices also contain microprocessors to convert user commands such as “print” into infrared light pulses. The receiving device deciphers the signal, converting it to an electronic command that tells the printer what to do. Some printers have IrDA built in, but any printer and computer can be made to communicate wirelessly through IrDA adaptors. For more information about how IrDA printers work, please visit howstuffworks.com.
IrDA printers have one big disadvantage: In order to talk to each other, they must see each other. Although infrared light is invisible to the human eye, IrDA devices detect it and must have an unimpeded line of sight between them. If an object or a wall blocks the path of the infrared beam, the printer can’t receive the signal. The two devices also need to be relatively close together.
Because of these limitations, engineers developed Bluetooth and WiFi, which have gradually overtaken IrDA printers in popularity. These new technologies rely on sound (radio waves) instead of sight (infrared light) and can travel through most walls with only mild signal loss. Bluetooth has a distance limitation of about 30 feet, but WiFi can be used up to around 300 feet. All three technologies can be used to network multiple computers to the same printer.
Despite these recent advances, IrDA printers still have advantages in some settings. IrDA printers are quite secure, whereas Bluetooth and WiFi can be vulnerable to hackers. In some environments, interference makes radio-wave based wireless systems useless. As long as the line of sight is clear, IrDA printers are usually free of interference problems. IrDA is also the least expensive of the wireless printing technologies.