This article is to diagnose healthy communication in your system.

Make sure everything has power plugged into it and is connected properly.Plug in the power cables into your protected power source, and connect the cables correctly.
Make sure the device(s) is switched on.Move the power switch on the device to the "ON" position.
Check the PCB (regulating electronics) indicator lights are on.Check the power fuse. New fuses can be purchased.
If the fuse is good, but the lights do not turn on, the PCB likely has something wrong with it and must be sent in for repair.
Check the PCB (regulating electronics) indicator lights. There should be two lights on right next to each other.If the light on the bottom and top are on, then the PCB is stuck in boot-loader mode. Let your machine sit overnight, unplugged. If the problem persists, you may try updating manually or it needs to be sent in to be reprogrammed.
Check the Robot/Butler indicator light and make sure it is blinking.If the light is not blinking, then the robot needs to be sent in for repair.
Make sure there is not a USB plugged into the hub (little black box behind the tablet) during normal operation.The only time a USB should be plugged in is when transferring files.
Check the version numbers under "System Information" are not listed as N.C (Not Communicating).
The machine version correlates to the Perfect Stitch regulating electronics.
The robot version correlates to the Butler quilting robotics.
If you do not have one of our products, then it is normal to see N.C. on one of the versions.
If you have a robot and the robot version is N.C. or you have our regulating electronics and the machine version is N.C. then the cable may need to be replaced (which can be purchased for replacement).
It is also possible that the robot/regulating electronics that aren't communicating have an issue, in which case would need to be sent in for repair.
Because communication is linked tightly to the display, check out Display Won't Turn On/FTDI error for more communication diagnostics.Check out the article Display Won't Turn On/FTDI error.

How to Send in My Product for Repair

If all those tests pass and are behaving normally, you can positively say your system is communicating as intended.

If your machine is still having problems, then we recommend doing more field tests to identify what to do to get your machine working as soon as possible.