ok sorry... let me back up... any device that talks to the outdoor board, like your intelliflo, salt cell, indoor panel, etc. will connect to the comm port, which is just an rs485 bus (sortof like a serial port)... the bus is shared by every device, so any device can misbehave and make it so any/all of the other devices can't communicate. we want to isolate the device we think is failing.
what you want to do is shut down power to your panel, pull everything off the comm bus EXCEPT the indoor panel... then power back up and see if the indoor panel works (without the possibility that something else is interrupting it).
the reason we do this is that something as simple as corrosion on the comm port pins, or the wire going from the outdoor panel to the indoor (did you check that per Allen's suggestion?) being knicked, waterlogged, cut, whatever can cause problems for other devices. Another example would be your screenlogic doesn't work so you think it's broken, but the real cause is that the is10 spa controller got water in it and nothing is really working