#

Octothorp, octothorpe, pound sign, hash mark, or square. There is disagreement about the origin of the symbol, although many agree that it was invented by scientists at Bell Telephone Laboratories (Bell Labs) in the early 1970s to designate one of the special function keys on a touch-tone telephone keypad.

(The other is the *, or asterisk.) The # is found in the lower right-hand corner of the standard dual tone multifrequency (DTMF) keypad grid. See also DTMF.

• FTC (Federal Trade Commission)
• FTP
• FTTC (Fiber-To-The-Curb)
• FTTN (Fiber-To-The-Neighborhood or Fiber-To-The-Node)
• FTTP (Fiber-To-The-Premises)
• FUBAR (Fouled Up Beyond All Recognition)
• FUD (Fear, Uncertainty, and Doubt) factor
• full duplex (FDX)
• full mobile number portability (FMNP)
• full mode
• full rate ADSL (full rate Asymmetric Digital Subscriber Line)
• Full Service Access Network (FSAN)
• FUNI (Frame User Network Interface)
• further
• fusion splice
• Future Public Land Mobile Telecommunications System (FPLMTS)
• FWM (Four-Wave Mixing)
• Fx (Firefox)
• Fx (Firefox)
• FX (Foreign eXchange) circuit
• FX (Foreign eXchange) circuit
• G
• G.711
• G.721
• G.722