They never had the "ringing" right and always used the double-gong
> ringers that one would find on 500/2500 type phones. When using
> payphones they'd have the "ding-ding" sound from a regular fortress
> type phone. The last "ding-ding" pay phones were the three
> slotters!
TV shows were notoriously inaccurate in ringers for telephones. I believe the phone itself does not ring, but rather the sound is provided off set and recorded separately. I've often heard 302-type ringers used for more modern sets and other strange bells used. In more modern shows, they've had a bell ringer for a modern tone ringer phone and vice versa.
Likewise with payphones. Long after 3-slot pay phones were replaced by single slot, the 'ding-ding-bong' sounds continued when someone used a payphone.
Of course, nowadays a ringer can be anything (even Jeanette McDonald's "When I'm Calling You") so the point is kind of moot.
Our local Bell business office lent our high school theatre group a Call Director set for a play. I wanted to 'examine' it but they returned it as soon as the play was over.