True story - I have voted on these machines.

Diebold brought some of the touch screen machines to my district for a real time demonstration to the Cuyahoga County BOE.  (County wide election, 2001)  They arrayed them one to a Precienct in the local High School, and I was asked if I wanted to volunteer to test them.  I accepted - They operated well enough, with each screen well arrayed and clearly understandable.  I do not remember if there was a summary screen at the end, so that you could confirm your vote.  After I had finished,  I was approached by two men, who I took to be from the BOE & Deibold - they asked for my impressions, I responded that I liked the machine, the screen was well organized and readable, and that voting was easy.  Both seemed pleased, until I started asking Questions.   This is how I remember the Dialog - the responses are from the Deibold rep.

How are the votes stored, memory or hard drive?
Hard Drive
What's the Backup strategy?
There isn't a backup - why would we need backup?
What happens if a hard drive corrupts or goes down - how are those votes counted?
At this point the Diebold rep started to reassure both of us as to the strength and reliability of their hardware.  I waited for him to finish...
How are the votes downloaded?
Excuse me? - I don't quite understand the question.
Are the machines downloaded to a central PC and counted there, or do they go direct to the county?
Direct to the county.
Over the Phone?
Yes.
Is the data encrypted?
No
Open line or VPN?
That would be For the county to set up.
What's to stop the phone transmission from being Hacked?
Dead silence.
How are they programmed?
The Ballots are uploaded by the county.
Are there checks of the programming running corectly?

At this point, the BOE guy looked like a deer in the headlights, and the Deibold guy was literally pulling him away from me twoard another precinct, while thanking me for my Interest...

I'm asking for paper ballots.