Apparently, other people have had the same question.

@Aesthetic_Mess Thanks!

@KTWBE No problem!

did that help? i didn’t really read through it thoroughly

@Aesthetic_Mess It helped me, thanks.

Synopsis of that and a couple of other things I Googled:

1)
Keypads existed decades before touch-tone phones, on adding machines for example. The 123 keys were at the bottom. picture

2)
Rotary phones also existed long before touch-tone, and had letters arranged like a modern cell phone. 2 = ABC, 3 = DEF, 4=GHI etc. picture

3)
When they created touch tone phones, they put 123 at the top, so the alphabet would run ABC DEF GHI, etc from top to bottom.

And woe betide you if you try to dial a phone from Europe or someplace with phones like those in Europe, intending to get 1–800-HELPYOU (or some such mnemonic) ... and you find that the keypads flat don’t have letters on them.

GQ

I can verify from memory what @jaytkay said. My Dad had lots of mechanical adding machines in his office, and I grew up using rotary phone dials. (Both devices, btw, have surprisingly clever mechanical designs in their own ways). When the Bell System introduced touch-tone phones with buttons, people remarked even then that the keypad layout was different from calculators.

And THIS is why I like Fluther way more better than Google or Ask.com. Except for the moderating part. Cowering…

It can be a trip going from working on a 10 key computer key-pad all morning to covering for a very busy telephone operator on her lunch break. Srsly.

FWIW… none of my phones has the 1 in the bottom left position; they’re all in the top left. Let’s see, that’s two mobiles, an office landline, a cordless at home and three other desk type phones. All #1 keys in the top left.

@CyanoticWasp Yes. That is the difference between phones and 10-key computer key boards and other 10-key calculating machines, like calculators.