The Matter Receiver is a block added by RFTools. It is a passive device that serves as a destination for RFTools teleportation, and is not operated directly. Matter Receivers require Redstone Flux (RF) power to operate.
Matter Receivers are automatically created at spawn when a new RFToolsDimension is created. They are created with a full RF charge but need to be connected to a power source for repeated use. They can be picked up and relocated if necessary.
If the Matter Receiver in a new Dimension is removed and not replaced, there is no other way of getting into that dimension without admin commands.