When you pick your phone you get what is known as a “dial-tone”.  A dial-tone simply tells the caller that the switch is ready to receive a phone number so that it can connect two parties.  If the caller does not respond in a short amount of time, the switch will send a very loud and annoying tone that if not responded to, will cut you off.  Only so many callers can gain access to the switch at any particular moment.

Most new phones work like a cell phone; that is, you dial the number then press send.  This eliminates the lag between dial tone and numbers dialed—which resolves the problem of too many people taking too long to dial a number.

“Where is the switch?”

It is housed in a centrally located building in your neighborhood called the Central Office. It usually looks like a large, mostly windowless fortress. The buildings are usually constructed to withstand natural—and unnatural—disasters to protect the heart of the local network.  Your phone line is connected by a vast array of cables, wires and equipment, that terminate at the central office.  This is where your phone line is connected to the rest of the world.

The Central Office – (CO)

The Central Office (or CO—what the industry calls it) —houses the switch, in-coming and out-going cables, cable and equipment racks and a bank of batteries with power generators in case the local power goes out. Years ago it used to be a noisy place where mechanical switches opened and closed 24/7. But now the switch is an electronic device that only hums to the music of telephone traffic.

The switch interprets who you are calling based on the numbers dialed and sends the call down the correct cable. If you dial an area code that is different from yours, the switch knows you want to call someone outside your area. The next three numbers are called the exchange. This further tells the switch where in the neighborhood that person is and finally, the last four numbers identify who you are calling.

The cables leaving the central office are designed geographically in an orderly fashion. The cable leaving to the north is designated as Route 1, to the east Route 2, to the South Route 3 and Route 4 goes west.  These cables are designed in groups of wire pairs and those groups have numbers to identify them. A pair of wires is required for every individual telephone number—in most cases—depending on your service.

Fiber Optic Cable

Fiber optic cable has various configurations but they also have letters and numbers for the identification of each fiber.  These cables are connected to the switch through a dizzying number of connections on racks where each pair of wires or optic fiber is terminated.  Somewhere in there is your pair of wires or light pulse.  The same two wires that enter your phone must travel from your home or office to the racks.  Some of these racks house fiber optic equipment that interprets light pulse transmissions from the fiber optic cables.

Let’s follow a copper cable out from the central office and see what happens to it.  (See Figure 1.)

The Route 1 cable we will call “Cable 1”.  It is huge because it is going to end up at every service location in the northern part of the neighborhood—which could be miles away.

For the purpose of explanation, let’s assume this cable is 36 hundred pairs of wires (noted as 1, 1-3600).  It travels north underground through conduit and manholes—large underground concrete cable vaults that a man could stand in—and when it exits a manhole, it may go up a telephone pole or is directly buried.

It then branches off into smaller cables, like the limbs of a tree, and then goes through distribution cabinets to further divide the route until your pair enters your residence or business. The same thing occurs on the other routes. These 4 cable routes and central office that services it is called a wire center.

So how does your call get to your friend several miles away in another wire center?

Central offices are connected by a trunk cable. It is called a “trunk” because it is only used to send traffic between central offices or over long distances, and not directly to a customer.

See below.

When you dial a telephone number, the switch “knows” that the first three numbers are not in your wire center.  Your call is switched to the trunk cable that goes to the other wire center.  Once “switched” to that central office, the second switch interprets the whole number and sends a ring to the person being called.

All this switching occurs at a fantastic speed.  The labyrinth of central office to central office connections handles your calls to a larger area around your home or office.

Long Distance Calling: Phoenix to New York

Switching through every central office between Phoenix and New York is going to take too long and jam up local traffic. Never fear! The brains at AT&T worked out something to handle it.

An area code is a larger geographic area containing many wire centers. When you dial the area code for New York, your central office switch recognizes that your call is long distance.  The switch directs your call onto what is known as the AT&T Long Lines system.  It is no longer called
AT&T Long Lines but the concept is the same.

The figure below  shows a simplistic diagram of a Long Lines route. You can think of it as getting on the interstate highway instead of plodding along the
surface streets and stopping at every red light. Your call could travel through a number of Long Lines switching stations, but this is just an example.  These switching stations either pass the call to the next Long Lines station or send it to a local central office for routing, as described earlier.

To reach  another continent your call will need to cross oceans and other bodies of water.  Intercontinental cables were placed many decades ago to connect the U.S. with Europe, the Caribbean, and East Asia. A company branch of AT&T dropped huge lead-protected submarine cables off the back of a ship from one coast to the other—splicing them together as they went. These cables have since been replaced by fiber optic cables.

Telecommunication satellites are used to bounce intercontinental calls from one place to another. Once the call gets to the other continent, that country’s version of Long Lines picks up the call and switches it along as described previously.

Great—now we’re all connected!

Telecom Networks 101: Part 1

About the Author:

Saundra O’Neill began working for AT&T, and has spent the last fifteen years in utility design engineering for construction.  During this time her work in several fields of engineering (Civil, Structural and Telecom) established real world knowledge and experience in a wide variety of processes in the building industry with an emphasis on telecom Outside Plant and its processes.  Her experience and a desire to communicate/teach others, has expanded into technical writing – including software documentation and a variety of articles covering the telecommunications industry. Visit Sandy’s simple telecommunications blog.

]]> http://www.telecomauditguide.com/telecommunications/telecom-networks-101-dial-tones-switches-and-the-co/feed/ 2 http://www.telecomauditguide.com/telecommunications/telecom-101-origins-and-history-of-the-telecom-network/ http://www.telecomauditguide.com/telecommunications/telecom-101-origins-and-history-of-the-telecom-network/#comments Mon, 13 Dec 2010 19:59:00 +0000 admin http://www.telecomauditguide.com/?p=335 A good auditor is not only skilled in the myriad ways of finding savings throughout the vast landscape of telecom bills, contracts, CSRs, etc.,  he (or she) inherently possesses a thorough grasp of the origins and history of the telecom industry itself.

“Telecommunications” refers to something vastly different than it did just a few decades ago.  As recent as the early 1970s, “telecom” primarily referred to anything (and everything) to do with the telephone.   AT&T was the primary player, and cell phones, fax machines, the Internet and email were still years away.

Our new series entitled “Telecom Networks 101″ covers some basic areas that all telecom auditors should know.   Designed for the “non-techie”, the series of articles are easy to read and will give you basic insight as to how the telecom network of 2010 evolved over the last 140 years.

Telecom Networks 101: Who Built the Network?

A “network” could be defined as, any system of things that are tied together. The network described here consists of wire and optic cable, equipment, satellites, antennae, and microwave equipment that tie your home or business to the rest of the world. Without this network the Internet, cell and ordinary phones would not work at all.

To answer the question of who built this network in the United States, some history of the Bell System is needed.

The Beginning: The Bell System

The Macmillan Dictionary for Students defines telecommunications as, “…communicating or sending messages over long distances by electronic means….” The word literally means, communicating across a distance. The industry is known as telecom for short.

In the 1870’s Alexander Graham Bell spilled acid in his lab and called to his assistant in another room, “Mr. Watson, come here. I want you”.  To his assistant’s surprise he heard the call through Bell’s first telephone device. Interesting that the first reported telephone message was a 911 call! Since that time, there has been an explosion of devices that transmit information “across a distance”.

The first telephone company was founded in 1877 just after Alexander Graham Bell obtained a patent for the telephone in the United States. It was called the Bell Telephone Company. Existing telegraph wire was in place from Samuel Morse’s telegraph network and was used for some of the first telephone transmissions.

Others across the country were stringing wire and offering service to people in those local areas. As demand grew for this invention, new alliances were made to join local networks to each other and the world. This expansion became the American Telephone and Telegraph Company.

AT&T for Short

The name was shortened to the familiar AT&T and the network they created is known as the Bell System. This company had help from subsidiaries such as Bell Labs—big brains that invented the transistor and carried on Alexander Graham Bell’s legacy—and Western Electric that made telephones and other electronic equipment for telecom.

Litigation Changes Everything

Government watchdogs were already in place to regulate telecommunications; the Federal Communications Commission (FCC) on the federal side, and the Public Service Commission (PSC) on the state side. They approved how much was charged for service, watched over every new innovation, and investigated any report of abuse. In fact, they still do.

In 1974, The MCI Communications Corporation filed a lawsuit against AT&T.   This was coupled with an antitrust suit filed by the Department of Justice for the purpose of breaking up the monopoly. That suit was won in 1980 which caused AT&T to divest itself of Western Electric and Bell Labs. Regional companies—known as RBOCS (Regional Bell Operating Companies)—were created such, as Southern Bell—my alma mater.

Before the divestiture of AT&T, it was the largest telecom company in America.  It made sense, in the beginning, to have one company to coordinate this massive network.  They gave you a phone along with your service and controlled the whole market; including the manufacture of telephones and telecom transmission equipment. When you disconnected your service the phone was returned to the company.

This divestiture started a storm of innovation and competition. Up to that point, AT&T—and a few small regional companies—built the network that spanned the U.S. and connected the rest of the world. Companies were bought, sold, combined and divested. Recently AT&T merged with some of its old holdings.   It is hard to keep track, if you are not paying close attention. Suffice it to say, a lot has transpired since the 1970’s.

Alexander Graham Bell – the father of the Bell System. He worked with the deaf and was trying to find solutions to that problem. Little did he know his invention would be responsible for communications to the world with the touch of a few buttons—and make the Internet possible. The Internet’s use of this network has created countless ways to speak, write and transmit information across a distance.

About the Author:

Saundra O’Neill began working for AT&T, and has spent the last fifteen years in utility design engineering for construction.  During this time her work in several fields of engineering (Civil, Structural and Telecom) established real world knowledge and experience in a wide variety of processes in the building industry with an emphasis on telecom Outside Plant and its processes.  Her experience and a desire to communicate/teach others, has expanded into technical writing – including software documentation and a variety of articles covering the telecommunications industry. Visit Sandy’s simple telecommunications blog.

One of the goals of this research is to differentiate between those organizations that cut costs and maintained services from those that struggled to cut costs and made painful sacrifices that destroyed expected service levels for telecom and network services (Figure 1).  Read Full Article Here

Figure 1: Top Pressures Driving Telecom Lifecycle Management

Source: Aberdeen Group 2010 Read Full Article Here

What is a Telecom Trouble Ticket?

Trouble tickets are formal records that identify a problem, then assign responsibility for diagnosis and resolution of that problem.  A ticket could be as simple as a pad of paper with notes about the description of the issue, its status, the date(s) of carrier contact, name of carrier representative, resolution date, etc.  If your company is small, the chances of having chronic telecom issues are remote.  As the number of employees and field locations increase, it becomes imperative that a system for handling telecom trouble tickets is established.

Company workers can knowingly and inadvertently cost a company a small fortune in unnecessary telecom spending.

Employee abuses can be as innocent as using pay-per-use features that can and should be blocked to outright and systematic fraud.

The good news is that all companies can eliminate these abuses with routine diligence, strict company policies and “plain old common sense.”

This video shows 5 things you can do immediately to identify and stop telecom employee abuse.

For more information on how to gain control and reduce your corporate telecom spending, visit the TelCon Associates website.

Those words that began one of histories great novels (Charles Dickens, A Tale of Two Cities) could very well reflect some of the sentiment that is going on now world markets and industries.

As bad as things sound, and between all the talk and banter of worldwide recession, financial meltdowns, global meltdown and the imminent end of the world in general, the telecommunications industry’s future seems quite bright, thank you very much.

In fact, worldwide telecommunications industry revenues are expected to grow at a healthy rate of eight percent over the next 5 years, according to a new market analysis study done by INSIGHT Research Corporation.

Telecommunications revenue, including narrowband and broadband landline, wireless and cellular services, as well as Internet communications are expected to grow from $2.1 trillion in 2008 to more than $3 trillion by 2013 even as margins on traditional voice-related products continue contracting and the industry responds by shifting to an Internet Protocol (IP) communications fabric.

With voice revenues shrinking faster than carriers’ abilities to cut costs, landline and cellular companies are turning to IP technology to help reduce overall costs of operations. The upside of this shift to IP communications technologies is that customers should see a downward trend in costs over the next half decade. The downside is that networks will be increasingly more susceptible to outside attacks, an alarming issue that was rarely seen or considered in traditional phone networks of the past 100 years.

“The Future of Telecommunications 2008-2013″ evaluates revenue and subscriber growth in North America, Europe, Asia-Pacific, Americas, and Africa. Capital expenditures are also estimated by region and equipment class.

The full 119-page report contains considerable detail, but you can download a free report excerpt, table of contents to decide on purchasing or not. The report does not come cheap – a hard copy will set you back $3995. PDF copies are also available at a discount.

Get your free sample, excerpt, table of contents here, or call (973) 541-9600 for more details.