I do not think any of my USB Mini cables were provided by Garmin, most were bought on Ebay, shipped from Asia. But I bought some at Dollar Tree over a decade ago.
I have had one Mini USB cable not work as a data cable, it also had high resistance and would not pass much power for charging so I concluded it was defective and chucked it.
Some of my USB powered NiMH AA chargers also use the Mini USB cable, such as two of the chargers in the photo. But those are older chargers, the photo is over 7 years old.
If the OP does not have a Mini USB cable, he needs one for data transfer, which I mentioned in the first paragraph of post 12, above.
The photo above is from the last trip I did with one of the old Garmin GPS units with a black and white display, I could not charge AA batteries in the GPS so I had to carry more AA batteries on a long bike tour. Now I can charge NiMH AA batteries in my Garmin 64. (Garmin will tell you that it won't work but I used a work around so I can.) But I still need the Mini USB cable to do that.