A cursory search yields: The manufacturer doesn't want you to write your own patterns onto this type of card (or they want to earn big money to graciously allow you to design and use your own patterns).
- This card has a propriatary format, meaning there is no standard hardware to use it. You must buy a special card reader from the manufacturer (there seem to be a few manufacturers who support this card).
- The card you have is most likely read-only. They are intended to be marketed like a sewing pattern or a CD. The manufacturer writes one pattern onto the card and sells the pattern via the card to customers. I found some rewritable cards online, but for a much higher price.
- There once was a very expensive product called "Magic Box" by Brother that included a (hardware) card reader / writer and a software that could convert images into pattern formats and write them onto the card. As far as I read, the product is discontinued and it's impossible to activate the software, even if you buy it sedond hand.
In conclusion: "normal" users aren't supposed to write patterns onto these cards. An overwrite function was / is mostly intended for professional users (like shops or crafters who do commisioned works) and therefore very expensive.