SG-1 first encountered an Ancient transporter on P9G-844, a world once inhabited by the Ancients but now the homeworld to the Sodan. The very tall vine-draped obelisk stood in the forest near the stargate, and Ancient writing inscribed on its face described it as an aperture or gateway to enlightenment. The transporter was powered by clear control crystals that could be accessed by sliding out a panel on the side of the device, and it was activated by pressing three symbols on the face of the obelisk to enter a code. A brilliant light would envelope those standing near the device and instantly transport them to an identical obelisk elsewhere on the planet, where they would rematerialize. The Sodan referred to the Ancient transporter as the Eye of the Gods.
On the planet where Morgan Le Fay had once hidden the Sangreal, SG-1 encountered a similar Ancient transporter obelisk designed to be part of Morgan's security system to protect Merlin's weapon. In the cave on that world, an obelisk stood over the pedestal that held a holographic image of the Sangreal. Grasping the image activated the obelisk, which transported the team through the stargate to Merlin's cave on another planet. Less tall than the device on the Sodan world, this obelisk was similar in design but with different inscriptions and a diamond-shaped crystal that glowed as it activated. The device was used for localized transport, but was designed to be used in conjunction with the stargate. It too was powered by crystals in a panel that slid out from its face, and its programming had been set to dial automatically every couple of hours. The transporter's remote dialing program and command code would override the normal dialing protocols of the DHD, and each time it activated, Merlin's cave was transported through the open wormhole to a different world in a circuit of planets cut off from the rest of the gate system. When Carter and Ba'al were able to find the command override code in the transporter's crystals, the DHD could be dialed normally, and the team could return home through the stargate.
Cross Reference: Ancients, Crystals, Eye of the Gods, Merlin's Cave, Sangreal Planet
Episode Reference: Babylon, Arthur's Mantle, The Quest