Gate

Gates are devices which attach basic electrical logic onto BuildCraft Transport Pipes, Waterproof Pipes and Conductive Pipes.

Gates come in several versions; the standard Gate, and Iron, Gold and Diamond AND and OR variants on it, which have increasingly more options.

The difference between the AND and the OR gates, is when it will trigger an action. Both will trigger if one condition is true, but if an AND gate is used, and two or more conditions are set to trigger the same action, the action will only trigger when both conditions are true (If this AND this is true). If an OR gate got two or more conditions set to the same action, the action will trigger when either of the conditions are true (If this OR this is true).

Gates can send a signal along a pipe using Pipe Wire. To transfer a signal from a pipe that does not connect to another pipe (Waterproof to Transport), it is possible to use Cobblestone Structure Pipe.

When placing a gate on a pipe by a block with an inventory, a liquid buffer or an energy buffer, the gate will show conditions according to the block. An example would be to place it by a chest, and you would get inventory related conditions (Inventory empty, space in inventory, etc.). Some blocks or mods have their own conditions, like the Apiary and IC2 machines.

Recipe
Gates can be crafted with an Assembly Table, using at least one Laser. They require a Redstone Chipset of their type, and Pipe Wire.

You can switch between AND and OR gates, by putting them in a crafting table together with a Redstone Chipset.