Would anyone remember in what year dual-mode phones (keypad with a
> little switch to convert to pulse if necessary) came out in wide
> quantity? I think that was around the time they stopped using real
> ringer bells. My guess is the late 1980s.
Third-party manufacturers of phones for direct attach to the PSTN offered it from nearly day one. That way you could have th 'fancy looking' push-button phone _without_ having to pay the telco extra every month for Touch-Tone(tm) service.