Tunell Filament Sensor not working with Arduino Mega2560/RAMPS 1.4

Running Marlin firmware (not sure how to find out the version info?) that was uploaded using Arduino 022 software to an Arduino MEGA 2560 board with RAMPS 1.4 connected to a Windows 10 PC runing Repetier to drive GCODE.

The filament sensor is called a Tunell Filament Sensor available here Tunell 3D Printer Filament Monitor for filament faults – ToyBuilder Labs

022 config works and drives my printer OK. It is Slow, clunky but it does print and I was able to get the filament sensor installed using the instructions given on the toybuilder website. It was pretty simple- just a cut/paste of a few lines of code and connecting a couple of wires from the sensor to the RAMPS board.

Basically the sensor throws a Fault (PIN LOW) to the RAMPS (Currently I am on PIN5 cause PIN 4 is being used by my fan) when the sensor does not see filament rolling along and the pin state change throws a request to enque a M600 filament change code directly into the Arduino causing the printer to pause. All good so far right?

Well... I am using Repetier softwar to drive the printer and an add-on App (Repetier Informer) which pushes status messages (Start/Stop/Pause/Error) to my phone.

In this version of firmware, Repetier does not recognize the M600 command as a pause and does not notify me. This is dumb cause when the printer is out of filament (or jammed up) is when I DO need to be notified.

Contacted Repetier and they said... Update to new firmware and M600 will be recognized because of new scripts/handlers/etc. Sounds easy right? Not so much.

Contacted manufacturer of 3D Printer and got new Marlin firmware file. Got that installed and for some reason RAMPS/Arduino/Firmware does not recognize the Pin state change from the Sensor and does not trigger the Filament Sensor Runout Fault/M600 request and just rolls merrily along air printing without filament... uhg, frustrating.

Probably something simple because, like I said.... works on 022 but not on 1.6. Others have posted threads about similar problems but not in this 1.6 version and their suggested code mods do not correspond with with what I see on my screen in 1.6.

With the new 1.6 firmware loaded typing M600 on MDI line in Repetier results in flawless execution of this command. Next to try was M42 P5 S0 thinking that changing this pin state would trigger the whole Filament Sensor Runout Fault request. No Joy... just a strong desire to open anew bottle of rum LOL.

Anybody got any ideas or a rope you can throw me? THANKS!