No with the Cell Set solution, you do not use the aux port at all. The Cell Set connects directly into the intercom/CB/ HD radio setup with an electronic box that mutes the HD radio for about 5 seconds when the Zumo sends prompts(or phone or MP3). The aux port is not used and is still available for an Ipod or whatever. The cell set will still work even if you use the Aux port for another device. The Cell Set specifically uses the intercom/CB portion of the HD system which is separate from the radio/CD/MP3/AUX/Xm radio.
That is the key to why this solution works so well. As I said above, it
only works if you use a headset, as it use the HD headset functionality which has two audio circuits, one for the intercom/CB and one for the radio/CD/MP3/XM/AUX radio.
The Cell Set effectively does the same thing as pressing the CB talk switch or the intercom Voice activated by muting the HD radio. In fact the HD radio does not even have to be turned on for the Cell Set to work. Just the intercom (and maybe not even the intercom). It is a separate add-on electronic box (kind of like adding a CB radio to older ultras).
Other than needing to be pretty good with wiring harness's (you actually rewire the HD harness,fairly simple and very well done) and removing the fairing, it is the the most valuable add-on to my CVO. Use to not ride with a headset helmet, now only ride with it.
Also, helps to purchase a different headset system (the HD is OK) from J&M so the sound and volume is better (not required, the J&M headsets have great sound quality).
Three years with the Cell Set and it has been removed and reinstalled on all of the bikes. Great product. Not good Great.
We have about a dozen Ultra riders in my Chapter that have it and without fail no one would give it up.
And support from Kennedy is excellent. Had an issue with the volume on the bike and Kennedy figured out the Garmin mount was bad. Replaced it and all was well.