So anyway, enough sentimentality. I thought I would open up a BSTJ article at random. Sure enough, it was very interesting. The first article in the Jan., 1929, issue was Decibel--The Name for the Transmission Unit, by W.H. Martin, wherein the "db" was introduced to the technical public!
Why do we always use "db" instead of bels? AT&T had been using the "transmission unit" for some time, which indicated a ratio of 10**0.1 -- which was identical to the new decibel. It's a handy unit, too, because it is just about the minimum loudness ratio a person can detect in favorable conditions.