I've been up and down these forums reading about 6630 and it's Double Voltage version of the RS-MMC, and realized that my card from the 7610 won't work in my sisters 6630, but the question I cannot seem to get an answer for is if my sisters card, from the 6630, will work in my 7610.
6630 DV RS-MMC in 7610?
Yes, a DV card from the 6630 will work in a non-DV devices such as the 7610.
That's the idea of DV (Dual Voltage) cards; they support both the newer, lower ~1.8V (e.g., for the 6630 or 6680) and the older ~3.3V (e.g., for the 7610 or 6260).
It will work it is backward compatible. U can check the kingmax page for more info on DV RSMMC cards. Basically, it can support two different voltages.
I took my 64mb rs-mmc that came bundled with my 7610 when bought june 8th 2004, and it works fine in a newly bought 6630. Did they ship 7610 with dv rs-mmc?
Yes.