I found a rather interesting article describing the state of AT&T's conversion to MF sending by operators as of January 1949. Apparently, MF service first began on October 2nd, 1948 with New York, Chicago and Philadelphia; more cities would be coming online this year. The article also talks about what will be area codes and how the "whole country will become metropolitan".
So, here's a question I've wondered about before: What happened when an operator needed to send into a step tandem? Were the push-button dials on operator switchboards strictly MF senders, or did they send dial pulses too? How did this work? Did the operators have to determine what type of signaling a distant office required, or was other equipment involved (e.g.: a tandem switch) that did this automatically?
On one occasion in the 1970's, I was given a tour of a live operator position in a small toll-center office. The step tandem was in the same building; it served several step exchanges. The operator cord-board had a push button dial but the supervisor demonstrated how it was used by dialing a number in Albany which, being a 4A Tandem, would obviously accept MF tones. In fact, she made a point of showing how to press the "KP" button first, then the number (pulling 474-2000 out of the air), followed by the "ST" key. However, I don't remember her showing how calls were dialed into the local step exchanges. At the time, I didn't know enough to ask, so I'm asking now; I'd love to know more about how the manual toll-office switchboards worked.
Anyway, below is a link to the Associated Press article that piqued my interest; beneath that I pasted my own OCR conversion of it to text.
"The News and Courier", Charleston, S.C., Friday Morning, January 7, 1949
New Push-Bullon System Speeds Up Long Distance Calls
By HOWARD W. BLAKESLEE (Associated Press Science Editor)
NEW YORK. Jan. 6. (AP):
" A new, push button system to make long distance phone calls, twice as fast as before, was announced today by the American Telephone and Telegraph company.
You can, says the announcement, get your call through before you have time to make one straight-line doodle on your phone pad.
Average time for long distance calls has been two minutes. With push button it drops to one minute.
The push buttons are not for home phones. They will be used by the long distance girls. The buttons replace dials. Any long disranee operator can button-dial directly any home in the United States and Canada, when this system is complete.
You won't any longer hear the clicking. The buttons make no audible sound. But if static or something should accidentally let your hear, it will be a musical note instead of a clock.
Ten per cent of the nation's phones already are on the long-distance buttons. They are the 300 cities and towns around and connected with New York, Chicago and Philadelphia. In June, Cleveland and Oakland, Cal., will button in; Boston in October; Albany. N.Y. in June next year. Canada ultimately Will be in. Also the button links will be offered to the 6,000 Independent phone companies.
The announcement says there will be fewer cutoffs and busy signals.
The 10 buttons which the operator must push represent 10 numbers, this adds three to present dial systems of metropolitan areas. The whole country will become metropolitan. It will be divided into districts, mostly whole states. But New York state has five of these areas, and there are four each in Texas, Illinois, Pennsylvania and Ohio.
The operalor will push the 10 like this: first 505, which is the number of the state of New Mexico: then 431, the number of a central office in that state; then 4820 which is a home phone.
The button system was started October 2 last. If you got repeated busy signals, on week-ends, since then, in trying long distance, that was when the push buttons were being cut into your line.
The announcement says there have been no layoffs. None is expected, because so many new phones are coming in, nine million of them having been added in 1948. "