Last step-by-step-by-step exchange in Moscow

Last step-by-step capture

  • Stepping switch step-by-step exchanges
  • Stepping switch step-by-step exchanges

 

December 20 last year in Moscow was turned off in the last step-by-step-by-step exchange. We visited disconnects the object and photographed everything, how have reached. So it was that show you it’s all we could only now, three months later, but have reserved for writing cool room.

Impressions of the visit, of course, stunning. All those endless rows of racks, flashing lights and bristling with pins, wires and switches, — a last farewell of the outgoing pre-digital era. By the time we went up to the room where the station is located, it was already disabled, but especially for us it turned on for a few minutes again. And, you know, it bears no resemblance to modern PBX — it’s all itchy, and smacked his moves as a huge colony of insects.

The basis of the design step-by-step exchanges — stepping switch, click on the first image to see it. This is a toothed half-cylinder with an electric motor stepper, allowing this very half-cylinders when receiving an electric impulse to turn to a certain angle (the angle accuracy is ensured ratchet because of which in the first instance, and clicks).

When the user removes the PBX handset, the signal is an electrical impulse comes from his first stepping switch (called preselection), brush the crawler will rotate and stop when they found the very first free line leading to the next, the group, the seeker. When such is the subscriber receives a signal that it can start dialing (continuous tone). Further pulses are already on the dialer, prompting the group to turn finder and transmit impulses to the line finders. The number of hunters in this circuit depends on the number of digits in the room (the more, the better). When the extreme in this process cylinders are closed at the right room, the line is tested on employment. If it is free, and the subscriber to whom the call is addressed, picks up the phone, make the call terminated. When the conversation ends, and one of the interlocutors hangs up, all the stepping switch, snapping, back to their original positions. That’s about as far as we understand it. If you want details, you can read, as everyone describes experts. We want to draw your attention to the following: only one set of one issue caused by the movement of the station several electromechanical components. Just imagine how all this fumbling when the station was working at full capacity. And, mindful of the fact that the moving parts in the first place is bumped, loose and fall off, think about what such a station to serve 10,000 rooms.

It is this, the last in Moscow, step-by-step-by-step exchange is on the Petrovsky telephone node communications and has worked since 1974. It occupies the whole space 40 meters in length, width is also rather big — 12-14 racks in a row on both sides of the aisle:

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

Each rack is one stepping switch, you can look at them for a long time:

  • Stepping switch step-by-step exchanges
  • Stepping switch step-by-step exchanges

 

  • Stepping seekers step-by-step exchanges
  • Stepping seekers step-by-step exchanges

If you look closely at the overall plans, you can see that in the passages (both main and side) displayed multicolored lights:

  • Bulbs step-by-step exchanges
  • Bulbs step-by-step exchanges

 

  • Bulbs step-by-step exchanges
  • Bulbs step-by-step exchanges

They are illuminating, and alert your problem. These signals are displayed on the central display, followed by constantly monitoring station duty officer:

  • Control board decadic PBX
  • Control board decadic PBX

Light bulbs in each row and each column will help you quickly determine the location of the problem. A color coding allows you to quickly determine the type of problem and the urgency with which it must be eliminated. By the way, work on the decade-step telephone exchange is not an easy call: the non-stop noise in the room and quite hot, and the failure of varying severity occur frequently. Such work requires care and, preferably, light clothing, so working at the station mostly girls and women — often in thin coats on bare skin. Toolbox:

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange


  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

But the most important — The signal-calling device (And insulating mat)

  • The signal-calling device step-by-step exchanges
  • The signal-calling device step-by-step exchanges

This is the very thing that makes whistles and commands the connection and disconnection of subscribers. Fragments:

  • The si
gnal-calling device step-by-step exchanges
  • The signal-calling device step-by-step exchanges

 

  • The signal-calling device step-by-step exchanges
  • The signal-calling device step-by-step exchanges

And beautiful views bygone era:

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange


  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange


  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange


  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange


  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

 

  • Step-by-step-by-step exchange
  • Step-by-step-by-step exchange

After the station especially for us included, it specially for us was turned off. This main switch:

  • Master switch step-by-step exchanges
  • Master switch step-by-step exchanges

In a room immediately became very quiet, and we were taken a couple of floors below and see how the modernautomatic telephone exchange, which does not require constant human presence. The spacious, bright and quiet room is equipped with a special air-conditioned, is a neat row of cabinets:

  • Modern PBX
  • Modern PBX

That’s it — one PBX serving the same 10,000 rooms as step-by-step procedure, just cut off. Opposite him is another row of cabinets, that’s another PBX, more modern, instead of copper wire it uses fiber optics. To service the 10,000 rooms will need only two cabinet:

  • Modern PBX fiber
  • Modern PBX fiber

 

  • Modern PBX fiber
  • Modern PBX fiber

For comparison, one big bundle of copper wire — 1,200 subscribers, and lies next to fiber-optic bundle, it replaces the three large:

  • Copper and fiber optic cables
  • Copper and fiber optic cables

And this is how the wires go into the wall immediately clear where is the more modern exchange and in which case the connection and maintenance more convenient:

  • Copper and fiber optic cables
  • Copper and fiber optic cables

Prior to 2015, all exchanges in Moscow will be transferred to the fiber optic cable. Between themselves, they will also be connected optical fiber, which will greatly relieve the underground communications center. Then MGTS plans to replace copper fiber.

Today, Moscow has no step-by-step exchanges — the heroine of this record, most likely, already dismantled.

Many thanks to collaborators telephone exchange and its chief engineer for the detailed story, the press service of the Moscow Department of Information Technology for the invitation, and MGTS — for the excellent organization of the event.

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