Here is what the insides of the CNC Pendant look like. The 555 is on the left side and the 9 volt battery is only safe to use if all of your CNC inputs have opti-couplers. The cable is a 4 pair network cable.
This is the schematic diagram of the wiring of the direction switches. You need either 6 Volts or you can use 9 volts and a 5 volt regulator.
This is the wiring of the 555 timer and the power switch. Either use 6 volts or add a 5 volt regulator to protect your BOB (Break out Board) from the excessive voltages. I was using an old battery that was only putting out about 6 volts. You might also be able to tap into 5 volts from your CNC.
Here is what the DIY CNC looks like today.