Who invented the ATM machine?
The Jairus Larson Story:

In 1973, the Director of Systems, and person in charge of ATM development at Diebold, was Larry Smiley. Larry was a former manager of mine at Univac (now Unisys) and was also familiar with the consulting company for which I was working at the time. Diebold had constructed a prototype, stand-alone ATM and had started the process of developing an on-line version. The prototype was functional but was deemed to be too rigid and non-maintainable to market and mass produce. Diebold had an impressive programming staff but it was very inexperienced. Larry obtained a budget and offered my company a contract for me to develop a machine that they could sell. (I remember the first budget/contract was $50K.)

Diebold provided me with all the resources that I required. They gave me a separate room at their research facility, copies of all existing programs, and access to, and cooperation of, a small group of people that were developing what would later become the Diebold standard online product – the TABS 600. I had access to the Product Manager and all other relevant personnel.

Initially, I analyzed the system flow and dissected each and every program. After that, I was able to determine what could be used, what should be discarded or replaced, what needed to be modified, and what new functions/programs would be required. During the construction phase, Diebold assigned two of their programmers to assist me. The product developed (TABS 500) was a stand-alone model. The first installed Diebold ATM was a drive-up model installed in Atlanta, GA.

The on-line ATM was not ready when the stand-alone ATM development effort was complete. Larry was, of course, familiar with my communications experience. I had previously developed three communications message switches (Army, Navy and CDC/Litton Industries) plus a high speed data communications system for NASA. He asked me if I could add communications to the stand-alone version. The benefits would be:
1) A transition model for the existing banks.
2) At the time, ‘front-end’ systems for the banks did not exist – an on-line/off-line version would enable the ATM to go off-line when the bank communications was down. The ATM would always be open.
3) Anything that I developed could probably be used by the existing on-line development group. In that regard, I do not recall specifically, but I am sure that I was also able to use parts of what had been developed to-date by the existing on-line group. The resulting model that I developed was called the Diebold TABS 550. As far as I am aware, it was the very first online ATM. The first TABS 550’s were installed in Seattle and Spokane.

Some of the other principle people:
Roger Hellwinkle – a Diebold programmer that assisted during the construction phase.
Don Chick – another Diebold programmer that assisted during the construction phase. Actually, Don was the creator of the screen presentation system that I believe gave Diebold a huge advantage over the competition. It was the one part of the prototype that I did not need to modify one bit.
Tim Stock, Sam Stewart, Bob Green – the team that developed the online TABS 600.
Dick Clemmons – I am not completely sure about his contribution but I know that he was involved with the off-line prototype.