The parallel breakout board has a relay that can turn the router on and off according to the control software in the computer. The router will turn on automatically prior to the machine moving (a time frame can be set so the router is up to speed). When the machine is finished and is not moving, the router automatically turns off. This is with the m3, m4, and m5 codes in the g-code.
If you are interested in the USB breakout board, you will need to get an independent relay board.
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HOW CAN THE ROUTER BE CONTROLLED BY COMPUTER?