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What is inside a Central Office?

Started by princessphone, December 09, 2014, 11:01:29 PM

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princessphone

I'm just curious. Down my street (residential neighbourhood) is a CO. It's a relatively modern building, no windows, several security type doors, heavy duty loading door in the back. Usually during the day a couple Bell cars/vans parked on driveway, but very seldom see any employees. A couple of times I rang the door bell (and it took them a long time to answer), just to ask for some information, however I received a real cold reception and could not get a foot in the door. When I peeked inside, the passageway appeared to be like a fortified bunker. Does anyone know what going on in these CO's? I've heard or read that there's a lot of batteries in there. Maybe that would explain that there are a lot of vents on the building.
John DeJonge     

WesternElectricBen

I've been inside the small town central office which a friend maintains. Inside is the standard, modern line equipment including a time and temp generator. He has a couple computers inside for various reasons, too.

Besides that, he has the old switch setup just for fun.

Hope that answers your question,
Ben

princessphone

Thanks Ben. Actually I always thought that some sinister stuff was going on in there.

unbeldi

#3
Here is a link to a picture gallery (not mine) of a typical small central office as in operation today.

https://plus.google.com/photos/112147935665098825256/albums/5143859548219222753

The pictures show everything from the switch and the distribution frames to the battery shelves and generators to the garbage corner...

This is the DOVRNJDO facility which today hosts eight central office prefixes, but back in the 1950s it served the FOxcroft 1- and FOxcroft 6- exchanges, when it still had step-by-step switching gear.  Today it is a Western Electric 5ESS switch (now Lucent) and in some of the pictures you can also see Verizon FiOS equipment.

Russ Kirk

Excellent photos.

The reason it is built like is fortress is due to security. Often times the equipment in a CO is more valuable than the real estate. A relay rack/bay of equipment could hold $500,000 or more in equipment.  Cards alone could cost $25-50k or more each.
- Russ Kirk
ATCA & TCI

princessphone

Thank you unbeldi & Russ Kirk for the info. Great websites and pictures. A real eye opener to see all that stuff in such a relative small space and so clean and tidy and so few people. I never noticed a lot of cables going into the place so it must all be fed underground.
Thanks for the enlightment, John DeJonge

Weco355aman

Phil

princessphone

Thanks Phil, I'm really amazed. Is that a Princess phone I spotted in picture #19?
John
PS  I enjoyed the train stuff too. 

Lewes2

What about these companies providing VOIP, do they to maintain CO-type facilities or do they interface somewhere with POT operations. I don't even know enough to ask question!

Chuck

TelePlay

Quote from: Lewes2 on December 11, 2014, 06:02:33 AM
What about these companies providing VOIP, do they to maintain CO-type facilities or do they interface somewhere with POT operations.

From what I know, and that is both limited and sketchy, PCS providers have their own series of switches connected in several ways to their towers and the switches are indeed connected to a POTS central office. I would assume cable phone providers have the same set up but without the headache of wireless network management. I'd be interested in hearing from someone closer and more current with these networks and systems to set my comment straight.

TelePlay

Quote from: princessphone on December 10, 2014, 01:52:14 PM
I never noticed a lot of cables going into the place so it must all be fed underground.

Yes, they do, go underground that is. I don't have any good pictures of the large underground vaults but about 2 years ago, AE_Collector started a topic with information on the vaults that were ruined in New York by flooding due to hurricane Sandy. Here's the link to that topic.

http://www.classicrotaryphones.com/forum/index.php?topic=8040.msg87962#msg87962

Maybe someone has some good photos of vaults or links to them. It is simply amazing what is underground these days.

Russ Kirk

Here is a high level and very simplified explanation.

The cell sites are connected by microwave/fiber or even copper facilities to the local carrier (att/verizon) back the the cell carriers MTSO, or switching office. Some MTSOs are located in COs, some are not.

I will look later for some helpful diagrams I can share.....
- Russ Kirk
ATCA & TCI

unbeldi

#12
Quote from: Lewes2 on December 11, 2014, 06:02:33 AM
What about these companies providing VOIP, do they to maintain CO-type facilities or do they interface somewhere with POT operations. I don't even know enough to ask question!

Chuck

Today there is actually very little reason for a voice over IP provider to connect to a traditional central office which is very limited in the amount of bandwidth that it can provide. TDM access is very expensive compared to IP service.

The major carriers maintain data centers with softswitches that are directly connected on the national and international fiber networks. So all a provider needs is to connect to the softswitch over an Internet connection.

For example, Verizon has a business unit called Verizon Wholesale Business which runs a huge Nortel CS-2000 softswitch that can handled over a quarter million calls--last I checked some years ago, probably much bigger by now. A service provider simply routes and receives its customers' calls via SIP to/from the CS-2000.  The softswitch has access to any tandem or higher level switching center in the country that is owned by Verizon, and peers with other carriers as well.  Such whole service costs fractions of a penny per minute, depending on destination of course.

However, if a VoIP service provider sells last-mile service, meaning that they actually install a data line into your premises, in form of DSL over conventional telephone lines, then they have to install equipment into the colocation space at the local CO.