I had the fairing apart removing the cassette player and decided to take out the Kennedy cellset for my Zumo 550. It works fine, puts Zumo audio and telephone through the headsets but I may have used it twice in the last last year or so. Anyway if anyone is interested here what is included:
KT-CELL-INT-FPD 5 pin cellset intercom harness
KT-95413 cellset MC/GPS-ICS/MIC
KT-95423 Zumo device harness
A 12v power cord will be needed or one can be ordered from Kennedy for $20.
$130 includes shipping via USPS, parts list for $225.
More information and diagrams available at http://www.cellset.com/multigps.html