The Gateway Command is a circular device that can link to other systems, similar to how a portal works. The difference is that a portal is only made of energy, while the Gateway is a mechanical device.
The Gateway Command was invented by Professor Welman Matrix. Prior to the destruction of the Twin City, Mainframe had no ports to the Net and didn't have proof of other systems. The Gateway has two functions - search and link. It sends a series of pings through the void, programmed to lock onto energy bursts to seek out systems and link to them. This would prove that Cyber Space is not just an empty void, as thought by some Mainframe citizens. Professor Matrix designed the Gateway so Mainframers could theoretically find and visit other systems. Unfortunately, when he finally activated the Gateway, it locked onto the largest power source it could find, the Super Computer. When it did, the most powerful thing there was the Super Virus Gigabyte. The Gateway transported Gigabyte to Mainframe's Twin City where the virus damaged the Gateway, causing it to explode. The resulting energy split Gigabyte into two viruses, Megabyte and Hexadecimal, and destroyed the Twin City. Welman and the rest of the city were nullified. A copy of the control circuitry for the Gateway was stored in Mainframe's Archives. (Cross Nodes) (What's Love Got To Do With It?)
In an effort to get to the Super Computer, Megabyte used Game energy to break into the Archives and steal the circuitry that runs a Gateway Command. He constructed the actual hardware himself, but had to have the circuitry board that operated the original device. His Gateway and the control circuitry were subsequently destroyed in a fight with Bob and Dot Matrix. (When Games Collide)
Two years later, Hexadecimal made it possible for Welman Matrix to communicate, despite being the Null Nibbles. His daughter, Dot Matrix, asked him to reconstruct the Gateway Command so that she could try to fragment the virus Daemon when she arrived in Mainframe. This time, it was set up to have a single target but multiple addresses as destinations instead, so anyone who stepped through would be literally "blown to the four corners of the Net". They didn't get the chance to try it, but when Daemon started her count down for the Net to self destruct, Hexadecimal volunteered to sacrifice herself and carry the cure by way of the Gateway Command to save the entire Net. (Sacrifice)
Two years later, when Megabyte returned, Dot came up with a plan to trap him by offering the Gateway Command as bait. While the Gateway was being moved to the Archives by the CPUs, Megabyte's ABCs attacked and stole it. The Gateway was taken to Level 31 in Giedi Prime where Herr Doktor activated it, targeting the Super Computer. Megabyte walked through it, only to remain in Mainframe. The Gateway Command he stole was a fake, and the entire operation was a trap. A CPU unit lead by Bob, Matrix, and AndrAIa attacked the virals and captured Megabyte.
When in the brig of the Principal Office Megabyte asked about the location of the true Gateway Command. Bob told him it was in the safest place, and Megabyte reasoned that it was secure in the Core Control Chamber. (Crouching Binome, Hidden Virus)
- The design of the Gateway is similar to the Stargate from the movie of the same name.