During today’s interview at the D: All Things Digital Conference Steve Jobs took some questions from the audience, a complete transcript is available from Engadget.

Walt Mossberg of the Wall Street Journal and Steve Jobs chat at D5 ConferenceWalt Mossberg of the Wall Street Journal and Steve Jobs chat at D5 Conference

During the session Jobs let go of some very minor details regarding the iPhone.

Q: Can you comment on the 2.5G nature of the iPhone?

A: Interesting thing, it automatically switches to WiFi automatically — I’m in this industry, we were the first to ship a laptop with WiFi, shipped the first G, first N routers… If you choose to join a network it remembers that. But if you’re in a place and you want to join a WiFi network you haven’t joined before it prompts you. But it’s EVERYWHERE. There’s like 10x more WiFi out there than I ever thought there was. WiFi is faster than any 3G, and EDGE is very fast too.

Q: All indications appear that the iPhone is closed, we’d love to develop apps…

A: This is an important tradeoff between security and openness. We want both. We’re working through a way… we’ll find a way to let 3rd parties write apps and still preserve security on the iPhone. But until we find that way we can’t compromise the security of the phone.

I’ve used 3rd party apps… the more you add, the more your phone crashes. No one’s perfect, and we’d sure like our phone not to crash once a day. If you can just be a little more patient with us I think everyone can get what they want.

Jobs also fielded questions on iTunes.

“You can buy movies off iTunes as well. It’s pretty good quality — we arent selling high def… at this point. But I think in the future that might change!”

“Walt asks if iPhone will allow over-the-air video downloads. Jobs says no. It doesn’t make sense to buy media that way. Delivery over the airwaves is too costly”