Chamblee54

It is a question for the ages…why do telephones have 123 on the top row of the keypad, while computers have 789? The best answer is , we don’t know.
Calculator/computer keypads were an improvement on cash registers. These devices had a matrix of buttons, with the 9 row on top. The row at the far right had single digits, and the row next to them had digits ending in one zero. To ring up a sale for $1.95, you had to push 100, 90, and 5. This evolved into the adding machine configuration of three rows of three buttons, with 0 on the bottom row and 789 on the top row.
When we got started, the telephone used a dial. 1 was at the top, and 0 was at the bottom. The early phone systems used letters as part of the phone number. The first three letters of the seven digit code were two letters and five numbers. (This is what PG remembers from childhood. It may have been different before then).
The two letters referred to an exchange, or part of town where the number was located. The two letters referred to a word. An example would be PG’s grandmother. Her number was TR2 2345. The TR stood for Trinity. Many numbers in midtown Atlanta still start with 87.
In the sixties, ma bell started to develop a keypad to use for what were then called push button phones. In a break with the adding machine tradition, the numbers 123 went on the top row. There are a few ideas why this is, but nothing is certain.
In the early days, the phone switching equipment was not as fast as today. Some thought that by switching the numbers to the top of the keypad, people would have to slow down a bit to “dial” the number. This answer does not make sense to those of us who have grown up with these keypads, and who learned to punch in numbers fast, no matter what system is used. (Anyone using a rotary phone, after getting used to touch tone, is shocked at how slow it is.)
Another concept is the phone company wanting to model the new keypad after the dial phones. This would mean putting the 1 at the top, and 0 at the bottom. Also, with the letters assigned to each number, it would make a lot more sense to have 123/abc def ghi on the top row. It just looks a lot better.
It was suggested that the calculator keypad was patented in the 789-on-top format. Western Electric did not want to pay royalties on this important piece of equipment, so it designed another one. There is also the thought that the calculator was on a desk shelf, where the lower numbers should be at the bottom of the keypad. At the same time, the telephone was on the lower part of the desk, and having 123 on top would be easier to use.
Pictures are from ” Special Collections and Archives,Georgia State University Library”.