Does a VENSTAR thermostat compatible with a NEST thermostat

[youngsenior]

I was given a new NEST thermostat . I currently have a VENSTAR with five wires red , green, blue, white and yellow 

The system works but the wires are not matched up with the correct color . The nest has a QB port what is that for ?

Also are these systems compatible 

[Jake]

Hey youngsenior,

Sorry for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further. 

Best regards,
Jake

[Jake]

Hey youngsenior,

I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity. 

Best regards,
Jake

[Jake]

Hey youngsenior,

It has been a few days since the last reply, and I am going to lock the thread at this time. If you have any questions, please feel free to create a new post. 

Best regards,
Jake