How a 1951 Step-by-Step Telephone Switch Worked
AT&T Tech Channel · Explainer · YouTube title: AT&T Archives: The Step-By-Step Switch
Why it's here
HN uses it as a favorite old explainer for mechanical telephone switching.
What it covers
A 1951 Bell System training film showing how telephone calls are routed through a step-by-step (Strowger) switching office.