With all due respect, Bell/W.E. did not design
>SxS. That was done by, or at the behest of, a Kansas
>City undertaker named Strowger, as I recall.
>
> When the first dial office was established in
>Oklahoma City, in 1920, it had to come from Automatic
>Electric, since there was none from Bell/W.E.
>
> Some of it was still is service into the 1950s
>and I think probably another 10 years or so late.
>(Additions to the office, and other SxS offices in
>Oklahoma City, starting in 1927, were W.E. equipment,
>since they had discovered by then that not all of the
>U.S. is served by great megaplexes and there was also
>a need for dial equipment for smaller cities where
>common control would have been, to put it mildly, an
>absurdity.
Step gone by the 1950's? Maybe in the Bell System, but not at independents - Try 1986 for the last "100% Mechanical Step" office, and at least 1992 for it to all be cut out of service through digital switch expansions and replacements.
Lancaster CA was the last SoCal GTE switchroom running 100% AE Strowger and all-relay Type 62 'rural' SATT. (They did not have a way to retrofit the Proctor/IBM Electronic Director system to a Type 62 office, so it kept chugging away - grossly overloaded.)
Local calls dialed 7-digit, and for toll you dialed 1 to get a director and second dial tone, and they shipped almost everything toll out to a tandem.
GTE was being rather pragmatic - they didn't want to install a bunch of 1A-EAX and 2-EAX 'analog electronic' reed-relay offices just to eliminate Step, and then have to yank those switches right back out again in 10 years when Digital was finally ready. They wouldn't have had them fully depreciated yet.
The mixed offices that started out Step and already had a 1A-EAX,
2-EAX, 5ESS or GTD5 installed for expansion were either expanded further or replaced to absorb the step and analog electronic prefixes. I was out of COE Installation and in Construction Splicing before they finished that.
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