How do undersea cables terminate?

June 28, 2005 10:41 PM

How do undersea (and trans-ocean) fiber optics communication cables and trunks terminate? Do they rise out of the beach like a giant mass and snake into some building or does it branch out under sea and connect underground? Question kind of prompted by curiosity about this outage.
posted by phyrewerx to Computers & Internet (8 answers total)

Best answer: Hi phyrewerx, the industry tries to be as secretive as possible about undersea cable landing areas and technologies, but the majority of modern undersea cables enter pre-built, protective conduits (basically a strong steel or concrete pipe) as they come near shore. These conduits typically lead them deep under the beach or marina by quite some distance. They then typically pop up to a (usually) small oceanfront facility where the actual termination point is (and the last of the "undersea" repeaters). From land you'll likely never see the cable itself. The protective conduits do a pretty good job near the shore, but the lines are still vulnerable further out. The largest risk these days is typically large commercial ships putting their anchor down in a storm and dragging past the cable (and destroying it in the process), as what happened in china in 02.
posted by jba at 11:04 PM on June 28, 2005

This is a pretty good rundown of the process.
Another good story, though not strictly related to your question, about cable pulling on a grand scale.
posted by madajb at 11:14 PM on June 28, 2005

I gotta reccomend that Neal Stephenson article that madajb linked. It's probably the best article Wired ever published.
posted by PenDevil at 12:35 AM on June 29, 2005

In Heart's Content (yes, that's the name of the town) Newfoundland, where the first transatlantic telegraph cable emerged, you can still see the end of the cable sticking out of the sand, about ankle-knee deep in the ocean. So at the very least they used to just rise out of the beach. There's also a museum about the transatlantic telegraph cables and the various attempts to lay them. Amazing stuff.
posted by duck at 4:49 AM on June 29, 2005

And if anyone believes that the major conduit for internet data to the entire nation of Pakistan (who woulda thunk it?) just happened to develop a devsatating fault on the same day a chopper carrying US special forces goes down in a remote area of Afghanistan and the president is billed as giving an important speech to the nation in front of a wall of flags and a facing a group of soldiers . . . Wanna bet they were hoping to reel in the Big Scary Guy just in time for last night's dog and pony show? Amazing what those Navy divers can do on demand. Sorry, a bit off-thread, but one assumes the powers that be have considered the security of cable landing sites.
posted by realcountrymusic at 6:28 AM on June 29, 2005

This classic Wired article by Neal Stephenson is a great read with lots of info about the whole process of laying undersea cables.

An excerpt:
One day a barge appears off the cove, and there is a lot of fussing around with floats, lots of divers in the water. A backhoe digs a trench in the cobble beach. A long skinny black thing is wrestled ashore. Working almost naked in the tropical heat, the men bolt segmented pipes around it and then bury it. It is never again to be seen by human eyes. Suddenly, all of these men pay their bills and vanish. Not long afterward, the phone service gets a hell of a lot better.
posted by jduckles at 6:31 AM on June 29, 2005

That wired article just took up too much of my afternoon! - great link
posted by brettski at 9:10 AM on June 29, 2005

For more on the first transatlantic cable that duck mentioned, try the History of the Atlantic Telegraph by Henry Field. A contemporary account of Cyrus Field's struggles to lay a cable across the Atlantic in the 1860's. Not really an answer to the question asked, but I found it a fascinating book when I read it a few years ago, and it gives an idea of just how hard these thing used to be, even if they are routine nowadays.
posted by Quinbus Flestrin at 9:15 AM on June 29, 2005