Infrared communication (IrDA) transfers data over short distances - a few tens of centimetres up to about a metre - using infrared light. The name comes from the Infrared Data Association, the industry body that drew up the standard. Fitted as standard to Japanese feature phones, it was widely used to swap address book entries, send photos and hand over business card data.
Using it meant lining up the infrared ports of two handsets, usually on the top edge, and operating both the sending and the receiving side. "I'll send you my contact by infrared" was an everyday exchange in 2000s Japan, and it was the standard way to swap numbers at parties and social gatherings.
Its defining traits were strong directionality, since the handsets had to face each other, and modest speed, only a few Mbps in mobile phone implementations. The flip side of that directionality was safety: because the beam went only where it was pointed, there was little risk of sending data to the wrong person nearby. Compared with Bluetooth it needed no pairing beforehand, but a hand or an object slipping into the path stopped the transfer. When it failed, the cause was almost always misaligned ports or too much distance, so resting both handsets on a table and leaving them still was the reliable approach.
As smartphones spread, infrared faded quickly as a phone feature. Exchanging contacts moved to scanning a LINE QR code, and file transfer to AirDrop, Bluetooth and cloud services. Features that found nearby users by shaking the handset also existed, and those too were later discontinued. As of 2026, only a small number of smartphone models still include infrared.
The technology itself has not vanished, though. Television and air conditioner remotes still send their signals by infrared, using exactly that property of reaching only the device they are aimed at. The practical difficulty today is recovering an address book still sitting on an old feature phone: the other handset needed to receive an infrared transfer is rarely at hand, so exporting to a memory card or using a carrier shop transfer service becomes the realistic route. For looking after the data afterwards see how to manage your smartphone contacts safely, and for how handset features changed see the history of telephone hardware.