Signal Transmission
Redstone Control uses its own Redstone system for transmitting signals between devices that is not based on placing blocks side by side.
Instead blocks have connector ports in different places on their surface that display a description when looking at them:
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Signal output / input ports -
Block Reference output / input ports -
Energy user / buffer ports
Signals are transmitted as signed 32-bit integers so they support a range of -2.147.483.648 to 2.147.483.647.
By the way, vanilla Redstone uses the same numeric type and therefore theoretically supports the same value range, it's just that vanilla and most mods don't offer anything to produce values outside the range 0...15 which is also what Redstone dust lines are limited to. However, there is no such limit for face to face transmission between adjacent blocks and many modded redstone cables may also (unintentionally) support more than strength 15.
There are currently three types of plugs that can be directly inserted into signal ports by right-clicking the port with the plug item in hand:
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Signal Status Lamp gives a visual indication of the signal emitted from the port and displays the exact value in the hovering text. This is very useful for troubleshooting circuitry. -
Constant Plug sends a constant value into the input port. The value is configured by right-clicking the item in hand before insertion. -
Clock Plug sends an alternating clock signal into the input port. The switch interval is again configured by right-clicking the item in hand before insertion. This can be used for all devices that require a clock signal to operate them continuously at a given speed.
Sneak-right-clicking a port with an empty hand or hitting it (in survival mode) will disconnect it and throw out any inserted component.
Signal Wire can be used connect a signal output port with a signal input port. After right-clicking the first port, the item will show a durability bar indicating how much wire length you have left to connect the second port with another right-click. A single item lasts for a distance of one block so it's a good idea to have a large stack of them at hand.
When a port is connected, its hover text shows a connection ID, for a more descriptive label you can use a 
Wire Tag on the port.
The connection is a straight line and may pass through solid blocks, however you can use 
Wire Anchors to customize the path and keep your wiring more tidy:
They can be placed anywhere within a 4x4x4 sub-block grid sharing the same block space with other anchors or non full block devices. Anchors are connected with wires in the same way as ports where each anchor can have one wire going in and one going out. They can be used with any type of wire not just Signal Wire.
This way signals can be transmitted over arbitrarily long distances while their value stays the same (there is no strength loss like in vanilla redstone). Also transmission still works if chunks in between containing Wire Anchors are unloaded as long as the actual devices communicating are loaded (changing signals also don't force load chunks).
There is also a 
Wireless Signal Connector that is used similar to Signal Wire except that it has no wire, no distance limit and can even connect across dimensions.
To connect blocks that operate with vanilla Redstone, there are the 
Redstone Read Socket and the 
Redstone Write Socket. Place them against the block face where you want to receive or emit Redstone. They can also be covered if needed.
Multiple sockets may be placed sharing the same block space while facing different sides. Different types of sockets may also share the same side.
There is one special configuration: you can place two Redstone Write Sockets on the same side in the same block to get a strong write socket that will emit a Redstone signal that penetrates through a solid block and power its adjacent blocks as well. However you can't also have a read socket on that side then.
Connecting a Redstone Read Socket directly with a Redstone Write Socket via wire will transfer signals with a delay of one tick but not alter their strength in any way.
Although standard Redstone signals are usually limited to 0...15 as previously mentioned, you can expect machines from other mods to interpret any value > 0 as active and 0 or negative values as inactive (like how vanilla blocks such as pistons, doors, etc. behave).