Comments by "ke6gwf - Ben Blackburn" (@ke6gwf) on "AT&T Tech Channel"
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This is very interesting, but unrealistic. They totally leave out the entire phone network and that these switches are rarely all in the same room.
A brief overview of the system, from old memory, but should be good enough to get the basic idea...
The wire from your house goes to the nearest Central Office, which is a room full of these switches, and on one side of the office is a bank of switches with one terminal for each subscriber or phone that it serves. So if you had 2 lines in your house, there would be 4 wires running from your house to the Central Office, and connected to 2 terminals on multiple switches.
(redundant so that the chances of all the switches that you were connected to being already in use was low)
So when you pick up the phone, one of the switches it is connected to which isn't busy rotates and selects the contact for your phone.
Then when you dial the first digit, that activates the second switch, which will select either to stay in this central office, or selects an available trunk line to another office in town.
The next digit dialed is passed through now to the remote office, and selects the correct group of switches in that office for the right side of town.
The next digit selects the bank of switches for the particular neighborhood, and the next digit selects the bank of switches for the right street, and the final digit selects the exact terminal for the wires running to your mother, because you should call your mother.
You can see why phone numbers got progressively longer, because the more possible connections you have, the more numbers needed to drill down.
In the early days you could only dial within your city or area, and if you needed to call long distance you had to call the Operator, who would select a trunk line in the direction you needed to go, the operator on the other end would answer, and then put the call through on their local system, and if you needed to call across the country, the operators might have to repeat this process through multiple interchanges in the cities along the way, until the route made it all the way to the end.
When direct dialing was introduced, they had to add the country code and area code systems which would select the trunk lines headed the right direction, and then keep drilling down. This was more complicated, because the area codes were not in sequential order, so when you dialed a 7, it didn't know whether you wanted 707 in California or 737 in Texas, and so it had to have some way of waiting for all 3 area code digits were dialed before it even knew which side of the country you connect to.
I can think of some ways to do it, but I don't know how it was actually done, but it was more complicated than just a simple city step system!
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