Why doesn't my teleporter work?

Check the following:

• Make sure you have enough power. The teleporter consumes a lot!
• Make sure you have the Link ID set properly. Teleporters must have the same Link ID, or use one of the wildcard signals (like anything).
• Make sure the two teleporters are the same quality.
• If you're using a mod that adds beacon effects to a wide variety of entities, then teleporters are probably getting affected too, but they weren't designed to be affected by beacons. Make sure the teleporter is outside of a beacon's area.

If your teleports are failing and you don't understand why, you can enable "Debug mode" via a setting, which will dump additional information to the console that might help you. (Or help me help you!)