I have just sold my old fully working Navman 7100 radio .
I had to clear the old mmsi number so as the buyer had a good as new radio .
well not one to spend even more cash .......this is how to do it..
Turn radio off. Press and hold "scan" and "esc" while turning radio on. Enter pin: - 7 enter 1 enter 0 enter 0 enter. Follow menu to clear MMSI and/or ATIS. When done, turn off and on radio, and follow menu to enter MMSI again.
It would appear logically that the pin code is just the model number, so it will probably work respectively with each Navman system??!!!