A failed cell test basically means that the 7706 was defaulted to potter settings instead of AES potter settings. Yes there is a difference. If you have a 7706 defaulted to the potter settings it turns the radio into a regular 6006 potter fire panel. If you use the AES potter default then your 6006 potter unit can use the pic and send signals on the AES network.
Below is the detailed explanation from AES help desk:
Solution # 0690 – E/R358 001 received from 7706-ULF Account
Subscriber out of network
On at least on one occasion, this was reported due to a bad RJ/Modular cable between the PIC (Panel Interface Card 7764) and Potter panel.
A more common reason may be because the PIC is not properly learned. Be sure to load the AES “7706-ULF AES Default Config.fpcf” configuration file available as a download from the AES Web site especially if the panel was reset to factory or the default Potter 6006 configuration file from the Potter software was used.
An example message is:
13 4321 18 E358 24 C001
Where 13 is Receiver #1, Line card 3.
New Event Code E358
Group or partition 24
Zone or Contact 001
This will be reported with E370 00 C001 from the 7788F portion as well indicating a problem with the Potter Panel or PIC in this case.