Bell Illustrated

I'll start out with some basic central office operations. I didn't bring my camera along the day I was getting a tour of the local E5(for my "school report"), but I can tell you it's a beautifull sight, especially with the e52k upgrade. DACS and MLT and cross connects, oh my!

There have been a lot of rumors over what companies use what switching equipment, for instance, GTE never uses Lucent equipment. Well I can tell you from first hand experience that every one of these rumors is FALSE. Sprint mostly uses DMS, but also owns ESS. GTE uses both, the density of any sort of switch with them depends on the region of service.

Starting at the frame, lines terminate on the horizontal side from CO equipment, such as the switch. The pairs will either be a standard customer line, or a special line, such as a t1 for pairgain or a test line. Some COs designate between the two by using different colors of cross-connects and 'carbons'(fuses on the frame) to differentiate. For instance, black for user pairs, orange or red for special lines.

Users terminate on the verticle side of the frame. As a rule, the left of the verticle and bottom of the horizontal sides are reserved for special lines, but this may not always be the case. Locating a pair on the verticle side should not be difficult; cable numbers usually represent a certain section of blocks(for instance a column), and the pair number will be listed on the side of the block. You will understand better once you see it.

      Typical pair number as shown on frame:   4-301
                                               \/\ /
                              cable number-----/  |
                              pair number---------|

So anyway, your pair will leave the frame and head toward the 'cable vault'. This is probably in the basement. The vault contains not only the main cable feeds, but also the UPS, and probably 2 deisel generators in case the UPS fails or drains. The cables will come out of the wall and head down a support frame, and are routed to the frame in one way or another, for instance directly through the ceiling. For a suburb, there may be 8 cables for a CO. This example is to help you get an idea of what is down there.

Cables are preasurized in the vault with the same sort of aluminum silver canisters you see around aerial lines, this is in case of a fire, or perhaps flood. If the cables are preasurized water will not get in, and as for the fire... that's just what I've been told, I don't see the logic behind it either.

The cables will be pushed through the vault wall, and that is the last you will see of them in the CO.

As for the office itself, they are usually heavily guarded and mysterious. They are almost always brown brick buildings, although lately bell has been building in residential houses... you won't even know an office of this type when you see one. They do this because people don't like 'intrusive' bell offices in their neighborhood. In case you disagree with me on this, I got it 'straight from the horses mouth' (gte tech that looked like a horse).

The office may or may not contain a truck yard. It may or may not be monitored with camera's. It may or may not have a locked fence and barbed wire. It all depends on what's in there, and how many lines they serve. I've been surrounded by police cruisers 5 minutes after leaving an office.. and i've hung around one for hours without problem. All offices, however, are monitored by a central beurau for security. They know when someone enters after 5pm, and they keep track of it. If necessary, they call the police.

The doors all use cipher locks(see pic below). If there is a stairway leading to a basement, you can count on it being the cable vault. The upper levels will contain the switch, outside plant offices, and business offices, depending on who's housed in the building. It's all arbitrary.

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