3rd Ave itself is slightly notorious - hosting the surface entrances for the Seattle bus tunnel, and a large number of inter-city routes, the area has a reputation for crime and the occasional death by shooting. It was a bit worrying to commute through, as a bus rider, and seems like an odd location for an ISP street-level office.
It became a USWest site in 1984 through the breakup of the Bell monopoly system, and then Qwest and eventually Centurylink.
There used to be some SAGE equipment at the Computer History Museum in Mountain View. I don't know if it's still there or not, but it was definitely interesting to see. The "light gun" user interface and the control consoles have a really pleasing aesthetic.
Edit: I'll wager it's a seismic upgrade. The building's vintage is from back when they didn't have as good of a handle on the seismic stuff. And the Cascadia Subduction Zone is no joke!
Just think of them as Stalin's New York Times - willing accomplices to Soviet genocide.
"Move along citizen"
Seattle, for example, also has the Elliot CO in Belltown: http://www.co-buildings.com/wa/206/
on this page is a photo of a 1200-pair: http://cityinfrastructure.com/single.php?d=RuralOutsidePlant...
"Ah there's your problem: you've patched the Fire Engine Red pair, it's meant to be the Ferrari Red. Rookie error."
It’s actually pretty simple. There are only 10 colors: blue, orange, green, brown, slate, white, red, black, yellow, and violet. They’re grouped in “binders” (using colored strings). You’re likely familiar with the first four pairs from network cables (which omit the white/slate pair). After cylcling through blue through slate paired with white through violet (25 pairs), the wires are bundled with binders starting with blue/white string. That gets you to 625 pairs (the first picture posted above is 600 or 625 pairs). After that, the binder groups are bound in a similar fashion (typically if you’re going beyond 625, the slate/violet binder is omitted to get a nice round 600 in the first group).
Wikipedia has a good article: https://en.m.wikipedia.org/wiki/25-pair_color_code
100-pair cable is only about 3/4” diameter. I have a 24-line 1A2 telephone that uses 75 pairs just to connect to the phone switch and two 100-pair cables feeding a telephone display case in my living room.
It takes me about a half hour to punch down 100 pairs on a 66-block. Old school telecom guys could probably do it in under 10 minutes.
At least I hope so, if not, then they really should exist.
The historic reasons from other posters give good justification for the current location.
Not saying correlation is causation here, but the interfernce is definitely a little unnerving.