You don't have to have a card - but it was easier for us to do that than trying to get my home PC and a 7.8m RIB within USB cable range!!
From memory, you can buy a data cable so you can just plug your GPS straight in to the PC and download the required data. We just went the card route because of the fixed GPS installation on the RIB.
I've read somewhere (probably on another current chart thread) that your unlock code is created using the part number of your GPS device - but I'm not sure if this is true. All we did was register the software, put in the unlock code, and away we went. There don't appear to be any more codes required - although as we had already registered our 188C with Garmin, I'm not entirely sure. I'd like to think that if I got anther GPS unit, the software would still work.
Dylan...
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