To fully understand remote controlling, let's figure a TV and VCR set with it's remote controls. The way the remote controls work, is generally using IR (Infrared). Infrared is light which is not visible to the human eye. The IR signal sent from the remotes to the devices (TV or VCR) are pulses of that "invisible" light arranged in a way the TV or VCR will understand, a little like your modem pulses electric signals to send/receive information with your ISP.