Infrared (commonly shortened to IR) refers to infrared communications. Most remote controls communicate via IR. The Puck uses IR to control Minisplits, Window ACs, and AV devices. Ceiling fans with remote controls often use RF (radio frequency) communications instead of IR.
IR devices communicate over line-of-sight. Obstructions such as walls, people or long distances may prevent IR transmission. It is recommend that you test the location where you intend to install a Puck for IR control before permanently installing it.