'I Love Lucy' can help you...
...understand how exchanges like "BUtterfield 8" were common in the 1950s and early 60s.
On many occasions when Lucy makes a call, she will ask the operator for the number giving the exchange version "MUrray Hill X-XXXX" for example.
I think the one most commonly used in the series (which may have been fictitious) is "CIrcle X" - in particular, a "CIrcle" phone number is listed as the contact info in the episode where Ethel appears on TV as "Mary Margaret McMertz" hawking "Aunt Martha's Old Fashioned Salad Dressing."
We lived in SoCal back then - the exchange at the time for our own section of the San Gabriel Valley was "PArkview" - which translated to "72" + "2" for the local area prefix.
I believe the reason for these named exchanges was that the phone lines all emanated from the same local circuit center, sort of like today's computers on a client server. And so the exchange centers were named according to the telephone company's protocol (whatever that was - perhaps geographic as in "MUrray Hill" or "AStoria Station" in NYC - which is a real neighborhood, but, then again, perhaps not, as in my case where "PArkview" in the LA metro area did not relate to any known neighborhood).
This was all back in the days before cellphones and more advanced circuitry/technology allowed for the phone lines to travel over wireless networks.
Back then, there was only ONE phone company - Bell Telephone (there were others but they were very, very localized) - and because of the way the circuitry worked and the phone company plans with cheap rates, there were also things known as "party lines" which meant that you shared your phone line with another party (or more?), in which case if you picked up the phone there was the possibility that the line was already in use (you could hear the people talking, and you were at your discretion to either hang up or ask them to get off in the event that you had an emergency to take care of. "I Love Lucy" addresses this issue too, in the episode where Lucy is waiting to receive a phone call from a game show but her party line turns out to be in use by two gossipy New York housewives; when the chatters ignore Lucy's plea that she has an emergency, she thinks up a quick "Lucy" scheme in order to free the line up!
"Don't call me 'honey', mac."
"Don't call me 'mac'... HONEY!"