Garage door opener

"Garage Door Opener." The device transmits a signal to the S.G.C. computer, identifying the SG unit and opening the iris covering the Stargate.

A G.D.O. and iris code (a sequence of numbers that must be manually entered into the G.D.O.) is assigned to every member of every SG team. The codes can be altered if one of the devices is compromised.

KEY EPISODES

Serpent's Song - The Tok'ra are issued their own G.D.O. and iris code.
Unnatural Selection - Probing O'Neill's mind, the advanced Replicators uncover his G.D.O. code.