Downstream, you might hit well over 1 Mbps; upstream, under 384 KbpsWhen the iPhone 3GS arrived last month, I explained the ins and outs of High Speed Packet Access (HSPA), the rubric that covers AT&T’s two highest-speed cellular data standards: HSDPA for downstream and HSUPA for upstream. It turns out that the iPhone 3GS is more limited than what I outlined in that article.