In 1992, you more options. Your friends could tell you for free, you could stumble on them yourself, or you could get them with a magazine or book (which you didn't necessarily have to buy, you could just flip through it at the store and memorize the cheats.)
> you'd call the Sega Hotline on a premium phone number
I remember the ads for that but I've never met a single person who did that. (Or whose parents would be okay with it.) Cheat codes were either shared by word of mouth among friends or in magazines. Or you bought a game genie, but that was more for messing around with a game's mechanics than actual, blatant cheating.
If you wanted to cheat in 1992, you'd call the Sega Hotline on a premium phone number and they'd give you cheat codes.
It's the same thing, just a different medium and middleman.