Land Line Network basics

How are landlines connected?
What are those boxes that you find in every street that a lineman peeps into and gets himself in jumbling those wires?
Why the hell do the govt people often dig out the roads for wiring down the ground?
How is my land phone connected to the exchange?

Guys all the above questions were in my mind.... They are getting cleared every day... So i feel its very important to share this information to the rest of the world...

Starting with Exchanges. Exchanges are the places where a landline cable starts till your home. They are the nodes or the end places where your call is being connected to other subscriber's line.
Cables are the wires that connect your landline phone to the Exchange (Local) through various other junctions or subnodes.
Ok to get a clarity on what i am talking about just see the below image. You can visualize how a network is established. Ofcourse all the exchanges are CONNECTED. Just to avoid confusion i have not connected them in the below picture.

Exchange: It is the place where the following functions take place.

• Subscriber has a meter to calculate his duration of calls
• Subscriber info is in his exchange.
• Connects to the subscriber through cabinets, pillors and DPs
• Place where the switching takes place to connect various subscribers. Till exchange the wires are independent.
• Depending upon the called user the call would be routed either to its own cabinet or to other exchange.

and many more... I think you can guess how a exchange would look like. If not pls look at the below pic.

Cabinet: Cross connection network between the primary cable and secondary cable as you can see in the first  figure. 

Cabinet consists of various CT boxes where the many primary cables terminate their conductors. Again there are set of CT boxes which take the connections and terminate out of the Cabinet to connect to a particular Pillor

Pillor is a Smaller version of Cabinet. It Cross connects the Secondary cable to the distribution cables. Pillor looks like below. Cabinet looks the same but with many CT boxes.

Then comes your Distribution Point. This is the point from where your landline cable comes into your house.

I guess you recognize with the pic below

Hey you know what they call the cable from the distribution point to your phone.

Its called DROP WIRE. It has generally two conductors and caries -48V. See the below image. The conductors are called A and B. 

From the exchange till the subscriber end, the cable consists of these pair of conductors to serve the calling purpose.

Now with this i end this connectivity. There are alot details about the cables. If interested pls drop a mail regarding your queries and i will be more than happy to reply you.