The transmitter block transfers a redstone signal wirelessly 200 blocks away. If you have a gravel block above or below it it will transmit for 500 blocks. The receiver block 'catches' the signal and activates or deactivates redstone that is attached to it. The transmitter can be placed in all six directions.
I've thought of several uses for this mod, including checking the status of your mob traps, routing a minecart from a station to the correct destination, sending an SOS signal, etc. See the video to understand how to use it.The recipe is shown in the video. Visit the minecraft forum thread for discussion and feedback.