Archive for August, 2007

BT’s New Business Divisions - a review

Thursday, August 9th, 2007


     The BT group  is on the process of setting up two new units BT Design and BT Operate  in addition to the existing divisions. This is said to  a second major change in the positive direction. The first  was the shift from  narrowband to broadband. Now BT is  getting itself converted  from a hardware company to a software-based services company


The BT group

            BT Group plc is the privatised UK state telecommunications operator. Formerly the company was called as British Telecommunications plc. BT, as it is commonly identified in UK, is the  dominant fixed line telecommunications and broadband Internet provider in the United Kingdom.BT operates in more than 170 countries and almost a third of its revenue now comes from its Global Services division.


            BT Group is  the largest communications service provider in world and  mainly operates in  the United Kingdom and in Europe.  Most of the telephone exchanges, trunk network and local loop connections for the vast majority of British fixed-line telephones are controlled buy BT. They are responsible for approximately 28 million telephone lines in the UK. BT has the Universal Service Obligation (USO) and is obliged to provide a fixed telephone line or a public call box to any address in the UK.


            Special government regulations by the British telecoms regulator Ofcom (formerly Oftel) control  BT’s businesses in UK. According to these regulations, BT is required to comply with additional obligations such as meeting reasonable requests to supply services and not to discriminate. In spite of theses constraints BT has expanded into more profitable products and services where there is less regulation in areas like . broadband internet service, telecommunications and information technology etc.


BT Group has already organised in to  the following business divisions:


?         BT Retail:  This division looks after retail telecoms to consumers

?         BT Wholesale: This division has wholesale telecoms core trunk network

?         Openreach:  This fenced-off wholesale division, tasked with ensuring that all rival operators have equality of access to BT’s own local network

?         BT Global Services: Business services and solutions (formerly BT Ignite and BT Syntegra)

?         BT Exact / One IT: consultancy and internal IT. There is some overlap with BT Global Services.

?         Group operations: This division  handles security, research and development, and other functions for BT Group Plc such as legal services.


New addition of service Units


            It is observed that BT is entering in to a second major stage of its transformation  from the 20th century style of functioning by creating two new business units. This change  is  effected with a view to ensure that  the company can keep ahead of the competition. The man power for these units are proposed to be found from with in the organisation. About 20000 employees will be drawn  from other parts of the business. The following are the  proposed units and responsibilities. 


BT Design

            BT Design will pull together IT designers from BT Retail, BT Wholesale and BT Global Services and One IT to design services on the 21C network. This group will be headed by Andy Green and  focus on the design and development of new services for BT Retail, BT Global Services, BT Wholesale, Openreach and the industry at large.


BT Operate

            BT Operate will take responsibility from BT Wholesale for the roll-out and maintenance of the group’s new IP based fixed-line network, known as 21C.


The vision

            Ben Verwaayen, BT’s chief executive observes, “My challenge is to help keep BT ahead of the game. Bringing together our world class capabilities in IT networks and process skills will give us unrivalled agility and renewed focus on operational excellence. This is the second phase of BT’s transformation. The first phase saw BT shift its focus from narrowband to broadband. This next stage is equally important. It will see BT advance from a 20th century hardware-based company to a 21st century software-based services company. In a software driven world, services will be available in real time and around the globe, harnessing the potential of BT’s 21st Century Network. The changes we are announcing today will drive new standards of excellence and shift power and choice decisively to customers”.


            It has to be appreciated that BT has taken a  bold leading step towards evolving  the organisational structure. In future the companies like BT should become self supportive to meet the stiff competition in the industry. One has to wait and  watch for the  results , since BT has gone in for larger challenging assignments.

Telephone Exchange - An overview

Thursday, August 9th, 2007


When we want to contact a person located faraway from us we use a telephone, a telecommunications device which is used to transmit and receive sound. Most telephones operate through transmission of electric signals over a complex telephone network which allows almost any phone user to communicate with almost any other. Our  sound signals pass through a number of electronic systems before reaching the destination. The interposed electronic systems may be defined as the telephone exchange. Depending upon the location of the caller and the receiver  the sound signals may have to pass through a number of exchanges.




Definition of telephone exchange

In the field telecommunications the word “telephone exchange” is defined as the an  electronic system that connects telephone calls. It is denoted by the first three (3) numbers of a telephone number, when you do not consider the area code.  If a phone number .555-1234 is considered, the number “555” indicates the exchange. This number is known as prefix. The telephone exchange or telephone switch  is normally housed inside a building along with other connected equipments. The building is called as the central office.


Central office


A central office is a structure used by the telecommunications department  to locate the  equipments  needed to process telephone calls and direct the data traffic. These offices are also known as  telephone switching centres, wire centres or telephone exchanges. A typical central office houses a main distribution frame (MDF) along with the cabling, PABX or central office equipment, MDF heat coil protectors,  grounding systems, radio and radar systems along with  communications-electronics (C-E) etc.


A brief historical overview  of  telephone exchange or central office


            In United State the  first telephone exchange was opened  in 1878 at New Haven, Connecticut. Soon  after the introduction of the telephone in 1878, subscribers were required  to “ring” the office to  get the help of  an operator to complete the call. As the number of telephone connections  expanded from only a few dozen to a few thousand, human operators were required to be housed in a central office building to complete calls.

            During the 1910s a large number of operators were engaged in front of switchboard to route calls day and night. During these  early days any call one makes whether next door or across town had to go through  the operator sitting at his/her switchboard.


            With the invention of the stepping switch device during 1891 the automation in the telephone circuit switching was possible. A number of step switches were  arranged in banks and integrated with a line-finder that detected the subscriber’s entry in to the circuit and hooked to a “dial tone” bank to show that the line was ready. This method varied from country to country.          

            Human operators were replaced with electro-mechanical methods of switching as the usage of telephones exploded. Now the operator was required to operate machines located in a defined “central” area  from where all telephone circuits radiate out to users. At this juncture the name  “Central Office” was coined. The name still remains  although the operators have been replaced  by technicians who repair and monitor the electronic hallways.

            In London the first telephone exchange was opened on 1 March 1902 with just 200 subscribers at the Savings Bank building in Queen Victoria Street and was under the control of the General Post Office. The exchange covered .an area of about two-and-a-half miles of the capital. Notable subscribers included the Treasury, the War Office and Fleet Street.  By 1905 the exchange capacity was extended to 10,000. The  ‘City’ exchange was  officially opened in November 1907 with a capacity of 15,000 lines to meet the growing demand. 

            In 1933, Faraday became the telephone centre of the world with the opening of the international telephone exchange.

            In 1935, an automatic exchange was opened with more than 6,000 working lines. The new exchange employed 60 engineers for over 15 months  for completing the task of switching subscribers over to the new exchange.


 Manual service exchanges


In a manually controlled exchange the customer lifts the receiver and contacts the operator to connect the call to a requested number.           When a  subscriber  lifted the receiver, a signal  lamp near a  jack would light on the panel in front of the operator.

            The operator then  would plug one of the answering cords available in the panel into the subscriber’s jack provided on the  switch board and ask, “number please?” by switching ON a headset.

            On getting a reply from the subscriber the operator might plug the ringing cord in to the jack of the called party. A ringing cycle is then started.



Pre-digital automatic exchanges


In order to  eliminate the need for human telephone operators, automatic exchanges, or dial service were introduced in the early 1900. Operators were replaced by computerized exchanges progressively. The telephone switch ,a device for routing calls from one telephone to another,  was introduced in the automatic exchanges. The switch formed part of the public switched telephone network that makes the exchange to sense  an off hook telephone condition and to provide a dial tone to that phone, When a number is dialled by the subscriber, the same is sensed based on the pulses or DTMF tones generated by the phone and then the call is connected to the called number with in the same exchange or to another exchange. The connection is maintained  until  one of the parties hangs up the phone. In this type of tracking the call is called supervision. A billing equipment  incorporated   in the exchange  counts the call duration and records the same. Another feature called automatic number identification (ANI) was also implemented.Motors, shaft drives, rotating switches and relays were used in the initial stages of development. Such exchange is called as electromechanical switches.


Electromechanical Signalling

The word trunk is used to mean a circuit connecting two switches. Signals are used to transmit information from the transmitting end of a circuit to inform a user at the receiving end that a message is to be sent.

Dual-tone multi-frequency (DTMF) signalling is used for telephone signalling over the line in the voice-frequency band to the call switching centre. Electromechanical switches using a variety of DC voltages and signalling tones  were used for communication with one another over trunks before the adoption of  Signalling System 7.