I love watching old movies and TV. Often times they have characters who use telephones via the old switchboard technology. Someone calls into a central system where their call is routed to the proper location.
How did those switch boards work? Especially in comparison to modern phones…
(I would also love any extra info on “party lines” where anyone could join)
In: Technology
**A manually patched switchboard** is simply a way of connecting one of many incoming lines to one of many outgoing lines (think of it like a freeway/roads) at a time when there was NO computers and complected switching was VERY expensive.
**To call from LA to London** – You would (1) dial the LA operator, who connects you to the (2) LA long distance operator, who connects you to the (3) New York operator, who connects you to the (4) US trans-atlantic operator, to be received by the (5) UK trans-atlantic operator, who connects you to the (6) local area London phone operator, who finally connects you with the person your wanting to talk to.
WHY?, flexibility, even today placing a call LA to London still follows the same connection flow its just done by computers,
**RE party line/ Manual exchange**
When I was young my uncle who lived in outback Australia
He was on a party line, The operator who was 18miles/30km away
The operator served 3 or 4 party lines each with 6-9 farms, (think like wheel spokes)
My uncles line was called “Cement Mills” and each of the farms was called,
Cement Mills 2, Cement Mills 3, Cement Mills 4, 5, 6 etc (the operator was #1)
**To Make a call** you wound a little handle, that turned a generator that rang a bell at the other end for the operator to hear (Normally ONE quick turn = one ring) the operator would then dial or connect you to who ever you wanted to talk to. IF you wanted to talk to the farm next door you wound a little handle the required number of times IE: Cement Mills 2, = 2 rings
**To receive a call** the operator would wind the handle the number of times that matched your number IE: Cement Mills 4, = 4 rings an you would know that it was a call for you. YES people could/would pick up by accident, yes they could hear your conversation.
**To call my uncle from town** you would dial the number of the Cement Mills exchange,
and ask the operator for Cement Mills 3
I hope this helps
Way back in the day, when telephone lines were new and neighborhoods were small and close-knit, people would share a single telephone line. Meaning, instead of dialing a number, you simply picked up the phone and “rang” the line, usually by sending a small current through to ring a bell connected to the phone. This would cause everyone’s phone to ring, and everyone would scramble to the phone to see if it was for them or someone else.
As more and more people became connected with this technology, it became apparent that having entire cities put on one phone circuit wasn’t an option. So different lines were split up into smaller sections, and instead of leading to each other, all of the lines lead to one area: the switchboard.
A switchboard operator would sit and wait in front of the board, and when a call came in for the operator, that output jack would light up. The operator would put a headphone jack into that line, ask who you needed to call, and then physically wire your phone line directly into theirs. Today we have massive server farms with computers set to automatically handle these connections, but this is where all of our telephoning terms come from.
Busy: someone else is already talking to who you need, meaning that there is a line into their phone already. You physically could not talk to anyone until the first person was done.
Operator: the person who would actually connect you to your intended recipient
Telephone technology back then was simply a more sophisticated version of two cans and a string, but the string is now wire and the cans are specifically designed receivers that hook to this wire together. When two people are on the same line, they can talk. We still use this basic form of telephoning with landline phones, which is why you can still pick up a phone in the house while someone else is using it and listen.
As for party lines, just imagine getting a third can and tying a new string to the middle one. Now speaking into one can let’s both others receive your voice.
Bonus fun fact: in rural areas that couldn’t afford proper phone line, people would sometimes hook their phones to their fences. Many of these fences had unbroken lines of wire that ran along multiple houses, making them a perfect substitute infrastructure.
Those switching boards connect individual users. Back then when you picked up the phone, someone in the call center answered it. If the line was free, then they would connect you to the other side. What they basically did is connect those 2 endpoints with a cable so you can directly talk to the other.
After that those switching boards where automated. That’s why we have phone numbers, so it can be done without an operator. Rotary telephones used electric pulses to tell the call center who you want to call. Later those rotary dials where changed to the push-button phones. Bell System developed it under the name Touch-Tone, also known as DTMF (Dual-tone Multi-frequency signalling), which is still used today.
Modern phones are much more complicated than the old ones, but the concept is the same. A mobile phone sends out a message to the call center that he wants to talk to this number. The call center then routes that traffic in the direction of the number (to other service providers network for example). If the other side is free then it’s sends back an OK. Audio codecs are selected as well.
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