Realize there are similar posts but have an interesting finding and not sure what to do with it.
As previously posted, sometimes the Aqualink RS will have all buttons lit and will read 6700 Rev C (or whatever your current revision is). This is typically reported as a communication error between the main board and the RS and the Jandy troubleshooting manual has some suggestions.
Interestingly, my iAqualink upgrade, which I installed in June, and which had been working perfectly, suddenly displayed this message. After some checking and e-mailing Jandy, they stated, 'We've seen this before with the AllButton controller (rectangular indoor unit) and the iAquaLink. There's a simple fix for it however, the installer or another service company need to come out and perform the fix'
They would not tell me what the 'easy fix' is.
When I checked the voltages between pins 1&4 of the communication link (which, according to the manual is supposed to be between 8 and 10 V), it read 19! Outside, it read 21 (so not much drop across the wires).
Any idea why this is happening?
Most likely I will try to install a small resistor to decrease the voltage and see if things return to normal but am worried this is a more serious issue.