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Speedy Cutover Service, SXS switching cutover to ESS filmed live at Glendale CA central office, 1984

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993K views11 years ago2 recommendations

History and cultureDistributed systemsHistory of computingNetworking and protocols

A historical 1984 AT&T film documenting the highly coordinated, rapid physical cutover from step-by-step switching to an electronic switching system.

A brief but surprisingly exciting 1984 video showing the preparation and live, real-time cutover from Step By Step switching system (SXS) to a new electronic switching system (ESS) in Glendale, California. Western Electric offered the Speedy Cutover Service to switching offices throughout the Bell System. Western Electric installers would visit a facility and prepare it, installing the new equipment inside the facility. They would identify and mark the existing cables that would need to be cut, then prepare employees for the cutover to the new ESS system. Previously a cutover from step-by-step (or from crossbar service) to ESS would take many frantic minutes, upwards of an hour, during which time active telephone service would be lost mid-call. With the speedy cutover service – 51 installers simultaneously cutting 927 cables as fast as possible, all on cue – the interrupted service could be brought down to well under a single minute. The climax here is unquestionably the moment of truth, the cutting of the cables, which is shown in real time. After making sure no emergency calls are underway, and with a shout of "Let's cut it!" the race is on, with three camera set-ups and a disco score capturing and preserving the moment of truth. Footage Courtesy of AT&T Archives and History Center, Warren, NJ

Why it's here

2 people recommend this

What people say. Recommended as a fascinating historical look at the extreme coordination and physical effort required to upgrade telephone switches with minimal downtime.

tjohnson Hacker News • Recommends

On “911 emergency services go down across the US after CenturyLink outage”

There's an old AT&T video showing the careful coordination and huge amount of manpower needed to upgrade a single telco switch. They had rows of workers with cable cutters, in order to literally cut the entire service over to the new equipment. Total downtime was just 47 seconds. (And even during the cutover, they're careful not to interrupt any emergency calls.) link to this video

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On “In 1930, the 22M-pound Indiana Bell building was rotated 90 degrees”

This1 is a great video on the topic of cutovers. Not quite downtime-less, but seriously impressive little amount of downtime in any case. 1 link to this video

anonsivalley652on Hacker News • Mentions

On “In 1986 Microsoft advertised Windows was available “except in Nebraska”. Why?”

Ma Bell had some ill ill communication. Those were the days, when the real paperclip payphone trick still worked. I'm not even sure pay-phones still exist in the Western world unless they're Tardises. Btw, here's a video from her vault about an actual cutover done in 45 seconds with a few dozen folks with big garden cutters: link to this video PS: I'm so old, I remember the days of operators, telephone books and fingers doing the walking. :) Speaking of old meets new, I recently used an antique rotary phone that's built into a brass end-table to diagnose an Xfinity VOIP call issue. It still works.

toast0on Hacker News • Mentions

On “Latency of old school landline calls vs. modern video calls?”

The central office switch that a landline is connected to is almost certainly doing analog/digital conversion. Digital switches were introduced in the 1970s and Analog exchanges were all but extinct by 2000 (according to 4, the last step by step exchange in Canada was replaced in 2002). If the call remains old school POTS, it will be essentially a T1/PRI call from that point on. Circuit switched digital calling was phased in over time, as CO switches were replaced. Chances are, a landline is actually handled by a remote terminal out in the field, and a/d converted there. Long distance (to most destinations) calling probably switched to digital trunks faster than local calling, because long…

mjclon Hacker News • Mentions

On “Telephone Line Rural Outside Plant”

There's some videos on the AT&T Tech Channel on YouTube that show inside the CO, like this one for the "Speedy cutover service": link to this video

somaton Hacker News • Mentions

On “Mainframe upgrade done with wire cutters (2010)”

Unrelated, but the title made me think of this video where AT&T failed over old switch frames to new ones by manually cutting all the cable bundles, very dramatic. link to this video (Speedy Cutover Service, SXS switching cutover to ESS filmed live at Glendale CA central office, 1984)