CNC Probe with DRO350

I'll add a circuit diagram at some point, but here is the details in words ...

The econo probe is designed to use with the inputs provided on many CNC breakout boards, which normally have an on board pull-up to +5V and generally that is 1k0, although some boards may need an extra pull-up. When using with the DRO350 or DRO550, the connections on the DRO need to be rewired to provide this pull-up internally. There are only two connections on the probe although it uses a stereo jack, but the signal is between tip and ring, with the ring being 'earth'. SO we need to shuffle the wires on the jack socket to compensate. tip comes off and gets connected to the end of a 1k0 resistor. ring + other end of resistor move to tip, and the 0V wire moves to ring. 

I'll add some pictures later, but shows an extra buffer fitted to the DRO550 to provide two econo probe type inputs as well as buffering the tacho inputs. The 1ko pull-ups are on the board.