**星空下的小小心灵3**: The Evolution in Telecommmunication : From Wire to Wireless

THE EVOLUTION IN TELECOMMUNICATION
The conveyance of messages by electrical energy, beyond the limits of hearing distances, evolved from mathematical theories and empirical formulae, derived from experiments on basic electricity and magnetism in the 19th century.

The significant inventions of the period 1830 to the end of the century ranged from the Electric-bulb to the phonogram, answer phones tape recorder and even the basic analogue computer in its rudimentary form. In the telecommunication sector, telegraphy, telephony, wireless communication, copper conductors and manual exchange are parts of a communication network had all been invented.

In essence, the period before the 1970s with predominantly analogue technology based equipment can be regarded as the analogue era; while 1970 to date is referred to as the digital information age.

The 20th century, development of appropriate improved technologies for achieving optimum quality of service and adequate quantity of facilities and services to meet the realities and needs of the age. Beginning of the information era, which was promoted by convergence of technology resulting from digitalization, is during the last three decades of the 20th century.

Telecommunication industry is principally divided to three or four sectors for manufacturing, marketing, operations and logistics of maintenance purposes such as Switching, Network Access, Terminals or Customer Premises Equipment and Transmission.

EVOLUTION FROM WIRE TO WIRELESS

Telecommunications channels make use of a variety of telecommunications media. These include twisted-pair wire, coaxial cables, and fiber-optic cables, all of which physically link the devices in a network (Wired Technologies). Also included are terrestrial microwave, communications satellites, cellular phone systems, and packet and LAN radio, all of which use microwave and other radio waves (Wireless Technologies). In addition, there are infrared systems, which use infrared light to transmit and receive data.

WIRED TECHNOLOGIES

Twisted-Pair Wire

Ordinary telephone wire, consisting of copper wire twisted into pairs, is the most widely used medium for telecommunications. These lines are used in established communications networks throughout the world for both voice and data transmission.
Twisted-pair wiring is wrapped or shielded in a variety of forms and used extensively in home and office telephone system and many local area networks and wide area networks.
Transmission speeds can range from 2 million bits per second (unshielded) to 100 million bits per second (shielded).

A normal traditional twisted-pair cable..oh wait..there's more..

..there's also this unshielded twisted pair cable with different twist rates which is known as UTP..and..

..in contrast to the unshielded twisted pair cable, we can clearly see that this cable above is shielded and it is called the S/UTP, also known as FTP

Coaxial Cable

Coaxial cable consists of a sturdy copper or aluminum wire wrapped with spacers to insulate and protect it. The cable’s cover and insulation minimize inference and distortion of the signals the cable carries.
These high-quality lines can be placed underground and laid on the floors of lakes and oceans. They allows high-speed data transmission (from 200 million to over 500 million bits per second- 200-500 Mbps) and are used instead of twisted-pair wire lines in high-service metropolitan areas, for cable TV systems, and for short-distance connections of computers and peripheral devices.
Coaxial cables are also used in many office buildings and other worksites for local area networks.

We never knew that some coaxial cables can be so colorful and trendy-looking ;)

The different layers inside a coaxial cable

Fiber Optics

A fiber optic cable consists of one or more filaments of glass fiber wrapped in protective layers. They can conduct pulses of visible light elements (photons) generated by lasers at transmission rates as high as trillions of bits per second (terabits per second, or Tbps). It transmits light which can travel over extended distances without signal loss.
Fiber-optic cables are not affected by electromagnetic radiation. The transmission speed of fiber optics is hundreds of times faster than for coaxial cables and thousands of times faster than for twisted-pair wire.
New optical technologies such as dense wave division multiplexing (DWDM) can split a strand of glass fiber into 40 channels, which enables each strand to carry 5 million cells. In the future, DWDM technology is expected to spilt each fiber into 1000 channels, enabling each strand to carry up to 122 million calls.

A fiber optic cable..and it's glowing too! Such an amazing technology

Here's how the inside of a fiber optic cable looks like

WIRELESS TECHNOLOGIES

Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems such as radio transmitters and receivers, remote controls, computer networks, network terminals and others, which use some form of energy like radio frequency (RF), infrared light, laser light, visible light, acoustic energy, and so on to transfer information without the use of wires. Information is transferred in this manner over both short and long distances.

Let’s briefly review some of these major wireless communications technologies:

Terrestrial Microwave

Terrestrial microwaves use Earth-based transmitter and receiver. The equipment looks similar to satellite dishes. Terrestrial microwaves use low-gigahertz range, which limits all communications to line-of-sight. Path between relay stations spaced approx. 30 miles apart.
Microwave antennas are usually placed on top of buildings, towers, hills, and mountain peaks, and they are a familiar sight in many sections of the country. They are still a popular medium for both long-distance and metropolitan area networks.

Hmm..does this object looks familiar to you? It sure does for us. Yes, this is a terrestrial microwave tower which you may have come across along some roads or highways

The diagram above is mainly about how a terrestrial microwave technology works

The Terrestrial-spectra which shows the different wavelengths that is transmittable through different planets

Communications Satellites

The satellites use microwave radio as their telecommunications medium which are not deflected by the Earth's atmosphere. The satellites are stationed in space, typically 22,000 miles above the equator.
Satellites are powered by solar panels and can transmit microwave signals at a rate of several hundred million bits per second. They serve as relay stations for communications signals from Earth-orbiting system.
These Earth-orbiting systems are capable of receiving and relaying voice, data, and TV signals for miles away.

You're now looking at the U.S. military WGSS communications satellite - such a beautiful and majestic technological architecture

This is an artist's interpretation of a GPS satellite, an image courtesy of NASA

Presently, communication satellites are almost all geosynchronous satellites. Geosynchronous satellites do not have high elevation angles. In Tokyo, for example, the elevation never exceeds 48 degrees. Buildings and mountains thus sometimes block satellite signals. Quasi-zenith satellites would overcome these problems.

This would certainly solve the "no signal" problems from occurring in cities with loads of skyscrapers like New York, Tokyo, London and in some parts of KL too..

Cellular and PCS Systems

Use several radio communications technologies. The systems are divided to different geographic area. Each area has low-power transmitter or radio relay antenna device to relay calls from one area to the next area.
Cellular phone systems have long used analog communications technologies operating at frequencies in the 800-900 MHz cellular band. Newer cellular systems use digital technologies, which provide greater capacity and security, and additional services such as voice mail, paging, messaging, and caller ID.
These capabilities are also available with PCS (Personal Communications Services) phone systems. PCS operates at 1900 MHz frequencies using digital technologies that are related to digital cellular. However, PCS phone systems cost substantially less to operate and use than cellular systems and have lower power consumption requirements.

A diagram on how cellular or PCS systems works

Wireless LANs

Wireless local area network use a high-frequency radio technology similar to digital cellular and a low-frequency radio technology. Wireless LANs use spread spectrum technology to enable communication between multiple devices in a limited area.
The use of wireless LANs is growing rapidly as new high-speed technologies are implemented. A prime example of open-standards wireless radio-wave technology is IEEE 802.11b, or more popularly as Wi-Fi (for wireless fidelity). Wi-Fi is faster (11 Mbps) and less expensive than Standard Ethernet and other common wire-based LAN technologies.
Wi-Fi wireless LANs enables laptop PCs, PDAs, and other devices with Wi-Fi modems to connect easily to the Internet and other networks in a rapidly increasing number of business, public, and home environments.

Peer-to-Peer or ad-hoc wireless LAN

Look closely..this notebook is actually connected to a wireless access point using a PC card wireless card

The wireless LAN, abbreviated as WLAN

Bluetooth

A short-range wireless technology called Bluetooth is rapidly being built into computers and other devices. Bluetooth serves as a wire- and cable-free wireless connection to peripheral devices such as computer printers and scanners.
Bluetooth operate at approximately 1Mbps with range from 10 to 100 meters. Bluetooth is an open wireless protocol for data exchange over short distances.

The well-known and widely-used Bluetooth

A bluetooth adapter which provides a wide-array of connectivity to hardwares in terms of communicating, sharing and data synchronizing

THE WIRELESS WEB

Wireless access to the Internet, intranets, and extranets is growing as more Web-enabled information appliances proliferate. Equipments like cellular phones, pagers, PDAs, and other portable communications devices have become very thin clients in wireless network. Agreement on a standard wireless application protocol (WAP) has encouraged the development of many wireless Web applications and services. The telecommunications industry continues to work on third-generation (3G) wireless technologies whose goal is to raise wireless transmission speeds to enable streaming video and multimedia applications on mobile devices. The wireless web service offers anytime or anywhere connection.