ANDREA SEABROOK, host:
Four decades ago, technology had different challenges. Engineer Jerry Merryman had been at Texas Instruments for two years when his boss gave him this assignment.
Mr. JERRY MERRYMAN (Engineer, Texas Instruments): He said we'd like to have some sort of personal computing device, maybe something that compete with a (unintelligible) that you can hold in your hand. It would have to have some buttons to input the problem. Maybe some neon lights or something that output the answer and, of course, it will work on batteries. You have to think of something. And, boy, we sure did have to think of something because none of those things were ready to go in 1965.
SEABROOK: A year and a half later, Merryman and his team produced the world's first handheld electronic calculator. That was 40 years ago this past week. Jerry Merryman went to a studio in Dallas to tell us about it.
Mr. MERRYMAN: It was about four by six inches, by about an inch and a quarter. And certainly, that would make a lump in your pocket but its predecessor in 1965 was a transistorized calculator that weighed 55 pounds set on a desk. Use enough power to plug in the wall and it cost $2,500 so…
Mr. MERRYMAN: …it was a pretty big change.
SEABROOK: One thing that strikes me when I - looking at your calculator here is that it doesn't have a screen, that it's got tape that comes out the side.
Mr. MERRYMAN: If you look closely, there's a transparent window. And you read the numbers on the tape. That's your immediate answer. Eventually, the paper comes out the side and you can save it if you like.
SEABROOK: And I gathered it's because the screen wasn't invested yet. There was no screen.
Mr. MERRYMAN: Well, light emitting diodes, the little brilliant red things, we were trying to make those in 1965 but they only put out infrared light. You couldn't see it. And we thought that a disadvantage.
SEABROOK: Yes. I could see that that would a disadvantage. What could your calculator do?
Mr. MERRYMAN: It's what was later called a four functions. It could add, subtract, multiply and divide. It had decimal point. It took in inputs up to six digits and made up to 12-digit answers. It printed about 12 characters per second. So the maximum time to get an answer was about a second.
SEABROOK: What were some of the challenges that you encountered when you were designing this?
Mr. MERRYMAN: Well, there weren't any examples of thin, cheap, reliable keyboards that would work a million times. Another problem was in all those transistors are going to use way too much power and you didn't want a car battery to carry around you. You want a little battery. We did some work on that. I remember making the battery charger myself in my garage. It was a sort of a little black fist-like thing that plug in wire that went to the calculator. And one of the most daunting things was testing the parts that we built.
Integrated circuits in 1965 had maybe 20 transistors and they had 14 or 16 wires coming off of them. Testing was fairly straightforward. We built larger chips that had thousands of transistors, although it had up to 120 wires coming off of them. Some of them are inputs, asking questions. And the others are outputs, giving the results. The number of combinations of that is just astronomical. And it was a daunting task to verify if any given piece of the calculator was doing its job. In order to solve that problem, we made a breadboard of the calculator - that is a model of it using regular integrated circuits. It occupied a two-tiered six-foot table with lots of visible wiring.
(Soundbite of laughter)
Mr. MERRYMAN: And we used it to mimic the calculation and then some subportion of the calculator was checked against the candidate chip and that was sort of a breakthrough in testing as well.
SEABROOK: When I was growing up, everybody had the calculators on their wristwatch. And one of the controversies then and before was that students could bring them to class and cheat by having a calculator in their class.
Mr. MERRYMAN: Well, you know, I don't see that as cheating. I see that as extending your reach and grasp. Maybe if students today are not so proficient with a pencil adding numbers on a back of an envelop, they've traded that for the ability to handle problems that were not in their purview before - in the same way that you might say that an automobile inhibits walking, but look how far you can go.
SEABROOK: Jerry Merryman joined us from Dallas. He is the man who invented -with his team at Texas Instruments - the first electronic handheld calculator. Thank you very much.
Mr. MERRYMAN: Thank you.