AT&T Tech Channel
1 HN recommender · recommended in 4 months, 2020–2023
8:26 · 774K views · Jul 25, 2011
A 1951 Bell System training film showing how telephone calls are routed through a step-by-step (Strowger) switching office.
HN uses it as a favorite old explainer for mechanical telephone switching.
4 comments from Hacker News
My favorite old explainer video, telephone switching (1951): this video About the Strowager Switch, which was invented by an undertaker who was fed up with the local telephone operators whom he suspected of diverting phone calls to his competitor.
In terms of the cloud providers other than the big three/four (AWS, GCP, Azure, Oracle) most of your Digital Oceans, Linodes (perhaps pre-Akamai?), etc of the world are almost all certainly colocated. As others have noted the "big ones" typically operate with a blend - green field physical construction for the big and dense facilities combined with floors/cages/etc in colocation facilities for areas around the world with lower hardware requirements. Colocation facilities are interesting (I've been in a lot of them) and they generally (physically) fall in two buckets: 1) Repurposing of old telecom (and even telegraph!) buildings. CoreSite (a colocation provider) has a few floors (last I looked) in The Telegraph Building in Chicago[0]. If you look at the pictures of the exterior of the building it still says Western Union on the side! There are some interesting aspects of these - most of them are located in downtown areas. If you start looking around in major cities you will start to notice gigantic nondescript buildings with minimal signage, almost no foot traffic, and almost no (if any) windows[1]. If they have any signage at all it will typically be "Something Bell", Western Union, AT&T, etc. These facilities are interesting for a variety of reasons. Because they are repurposed telegraph and telecom buildings going back to the days of mechanical telecom switching[2] and DC battery banks they have floor load ratings that are just incredible. Something like 20x or whatever of
I was honestly expecting it to start with things like arithmometers ( [LINK] ), Cooke and Wheatstone 5-needle telegraphs ( [LINK] ), or perhaps a dictaphone ( [LINK] ) and what about the rich history of fax machines such as the Pantelegraph ( [LINK] ). Here's a newspaper being printed by radiofax in the 1930s for instance ( [LINK] ) Speaking of communications, there's things like Strowger switches ( this video ) which I think count because that's what people were interfacing whilst using the phone (this became crossbars and relays in the 1910s and 20s respectively) Relays and telephone tech btw is how Electro the smoking robot from the 1939 world's fair worked ( [LINK] ) Even if we want to limit to computers, we have batch versus time-sharing flow, teletype versus graphical terminals and along those lines you have the work of groups like Evans & Sutherland in the 1970s (such as the line drawing system 1 [LINK] ) or Scientific Data Systems which was later acquired by Xerox. You also have the world of analog computers, the most famous of which is the slide rule. Even then you can go back to the 19th century Jacquard Loom, which even has a solution to "Hello World" on Rosetta Code ( [LINK] ) Then you have specialty machines such as the Fairlight CMI synthesizer with the lightpen interface ( [LINK] ) which really laid the groundwork of most DAWs to this day. For music there's lots of things. The theremin which you all know about but also things like Nikolai Voinov's "Paper Sound" [L
Worked at a telecom API provider and we were told AT&T still has a handful of these in service in the US. this video