LiftMaster 8500C compatibility questions

I would like to know if anyone can clarify to me if I can use a garage door controller type GO Control with the system Liftmaster model 8500C.
I know there seems to be a compatibility problem however I find that on my garage door opener system I have two wires that go from the contactor to get to the door motor. If I touch these two wires together my door opens and closes. So for me, this is a common system of garage door opener. If my reasoning is correct, a system such as Go Control should work?
If someone could guide me I would be very happy before making the purchase of a device that might not work. Thank you in advance for your advice and suggestions.
P.S. I do not own a Gateway 828LM from Liftmaster because there also seems to be a compatibility problem?

While shorting the red/white wires on the 8500 will actuate the door, doing so with the 888LM in place will most likely damage the unit as the 8500 supplies power over those wires to the 888LM.

If you’re dead set on using the GD00Z-4 with the 8500, you’d be better off hacking the 888LM, wiring it’s push button terminals to the control terminals of the GD00Z-4.

So if I follow you I will be better to buy the gateway 828 LM from Lifmaster and connect it to the Smartthings ?

That is what I use, but there is no official integration. I put one together based on @essidle’s initial device, tying it to a multi-sensor to avoid pinging the hell out of Chamberlain’s servers, but abandoned it after it was clear any SmartThings third party integration was a violation of MyQ terms of service.

Currently, I simply use a multi-sensor to notify if the door is open when it shouldn’t be, and use the MyQ app to close it if that is the case. Given the current state of SmartThings, I wouldn’t want it in control of my garage door anyway.

As with a number of folks here, the TOS violation may not be an issue for you, but as a software developer who expects our users to respect our license agreements, it is for me.

I understand your position very well and by the time Smarttings and Chamberlain find a common ground it will be my pleasure to follow your recommendations.