Early on (1920) the Bell System realized step-by-step would be inadequate for big city high calling volumes and developed and implemented panel switching for cities. However, Los Angeles already had step-by-step when Bell took over.
As Los Angeles/southern California grew in the war years (big defense aircraft plants, new postwar development), how did they handle the high volume traffic with step-by-step? Did they run into problems? SxS switches are limited to a 10x10 pattern and get very unweildy when it grows beyond that. I could imagine things got messy in the early
1960s before ESS was available. Were some SxS offices upgraded to a more powerful No 5 crossbar?
The Bell Labs says they considered developing common control senders as a front-end to SxS, but I didn't understand how far they went with that. They also did something called a "graded multiple" which apparently was a big help.
In the early 1950s NYC got network management, a control center for city wide traffic. It seems the Los Angeles area would need likewise in the 1950s or early 1960s.
Thanks.
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