Hi Kanopus,

I think you maybe right about XD cards. The link that I attached earlier shows someone using a SmartMedia card which is wired into a connector. Unfortunately the page referred to earlier in the article which I assume explained how to connect the chip is not available now.

I looked into using SD cards and MicroSD cards but as far as I can see they are serial devices and the SmartMedia card is parallel so that's not a simple swap. XD cards and SmartMedia cards are similar although I haven't looked at the pinout of XD cards yet.

The Garmin datacards are formatted with the Garmin USB card reader (which is also a programmer).