Does the DNI option require special equipment or is it just a choice of a decker to run in said mode?

Generally, IIRC, a decker is always running DNI as long as he or she is jacked into the deck or using a trode rig. If they are operating the deck with a keyboard or some other external device, the are not running DNI.

So, if I understand this correctly, a decker running in this manner (with DNI) then he would have a base initiative of 2d6 even without a response increase. Only when he (or she) is not running DNI would he have a base 1d6. Is this correct?

Right. Running on Pure DNI has its downfalls, too, though... so it's not always a good idea. Usually is, though.

What sort of downfalls should I expect?

I don't have my books handy, but I seem to recall that it's more difficult to resist black IC and dumpshock tends to be worse. Could be wrong, though.

Excellent, thanks.
So, basically all cyberdecks have the ability to let the decker choose between flying DNI or Standard Partial Manual Mode with no additional equipment. Is this correct?

I believe so. At least stock ones should. I think you can shave some time off by making a custom deck with a cold interface only, but don't hold me to that. (Hell, I may even have hot/cold and pure DNI confused.)

Yeah, pure DNI is definately different from hot/cold ASIST. You need hot ASIST to use Response Increase (and I think Hacking Pool), but it makes you vulnerable to black IC. Pure DNI from what I can see actually doesn't have *any* drawbacks, except a trode jack user can't do it. It's basically free +1d6 initiative at the cost of looking like a coma patient when you're jacked in.

Yeah, I see that you are right about the Response Increase (and the Hacking Pool) as neither can be used unless running with a Hot ASIST interface. When I read that about the DNI interface, I was really supprised. With the extra cumulative bonus to Initiative over Response Increase, I realized that I was running much slower than I needed to. My persona's Intelligence is higher than his basic Matrix Initiative, so there was another jump since DNI trades your character's Reaction for his Intelligence score when determining Matrix Reaction. If anyone knows any reason to not run DNI all the time, let me know, otherwise Swing Kid is running DNI all the time from now on.

no penalty. you'll look like a zombie, sure--but, then, with partial-manual interface, you look like a typing zombie, so it's not a huge loss.