Mobile phones took this cue from telephones, which have had this kind of notion of an associated set of alphabetic characters since at least the eighties or nineties.
>In the most areas of North America, telephone numbers in metropolitan communities consisted of a combination of digits and letters, starting in the 1920s until the 1960s. Letters were translated to dialed digits, a mapping that was displayed directly on the telephone dial.
Much earlier. Except that in most of the world they fell out of use before telephones became a common household item, so for people who grew up between, very roughly, the 60s and early 90s, mobile phones were the first phones with letters on them. We had heard about those strange phone "numbers" with letters in them via American television shows, of course.
Yep, apologies if I wasn't clear. I said "at least" since the late eighties and nineties since that's around when I first became coherent enough of a human to notice. I didn't intend it to be interpreted as "around" the eighties and nineties.
