Back in 1995, a small group at Apple-the main developer of FireWire-set about designing a symbol that could accurately reflect the new technology they were working on. 


Originally intended as serial alternative to SCSI, FireWire’s main allure was that it promised high-speed connectivity for digital audio and video equipment. So designers opted for a symbol with three prongs, representing video, audio and data. 


Initially, the symbol was red, but was later altered to yellow for unknown reasons. 


via The Secret Histories of Those @#$%ing Computer Symbols