Telecommunications refers to the electronic transmission and reception of signals for voice and data communications.

Telecommunications

InfrastructureCellular Network

Concepts > Telecommunications

In this chapter:

• Wireless Data Communications• Computer Network

In telecommunications, infrastructure refers to the hardware, software, and protocols that support telecommunications.

Telecommunications Infrastructure

Concepts > Telecommunications > Telecommunications Infrastructure

Telecommunications SignalsTelecommunications MediaRadio SpectrumTelecommunications DevicesTelecommunications Software

In this section:

Telecommunications signals are analog or digital electronic transmissions for the purpose of communication.

Telecommunications Signals

Data transmission rate is also referred to as the bandwidth and is measured in bits per second (bps). Bandwidth options fall into two categories: narrowband or broadband.

The terms broadband and high-speed Internet refer to a connection that is always on or active, such as cable and DSL.

Concepts > Telecommunications > Telecommunications Infrastructure > Telecommunications Signals

Telecommunications MediaTelecommunications media include anything that carries a signal and creates an interface between a sending device and a receiving device.

Concepts > Telecommunications >Telecommunications Infrastructure > Telecommunications Media

• Twisted pair copper cable consists of pairs of twisted wires covered with an insulating layer.

• A coaxial cable consists of an inner conductor wire surrounded by insulation, a conductive shield, and a cover.

• In contrast, fiber-optic cable, which consists of thousands of extremely thin strands of glass or plastic bound together in a sheathing (a jacket), transmits signals with light beams.

Radio SpectrumRadio spectrum, part of the electromagnetic spectrum, refers to all of the frequencies available for radio waves from about 10 KHz to 300 GHz and their assigned uses.

Concepts > Telecommunications > Telecommunications Infrastructure > Radio Spectrum

All wireless telecommunications—cell phones, wireless Internet, AM and FM radio—make use of radio waves designated to certain frequencies.

Telecommunications DevicesTelecommunications devices such as routers, network adapters, Wi-Fi access points, cellular towers, and satellites send and receive the signals employing telecommunications software that governs their operations.

Concepts > Telecommunications > Telecommunications Infrastructure > Telecommunications Devices

Network devicesHubSwitchRepeater Bridge GatewayModem (various)Router Wireless access point Firewall

Point/router/switch Satellite Cell Tower

A modem is a device that modulates and demodulates signals from one form to another.

Telecommunications Software

Telecommunications software is software based on telecommunications protocols used to • control• monitor load (amount of traffic)• troubleshoot data• provide security

traveling over a telecommunications network.

Concepts > Telecommunications > Telecommunications Infrastructure > Telecommunications Software

TelecommunicationsSoftware• Network operating systems (NOS)• Network management software

– monitor the use of individual computers and shared hardware, scan for viruses, and ensure compliance with software licenses.

• Telecommunications devices software interfaces• Firewall software• Standards

– Ethernet is the most widely used network standard for private networks. This standard defines the types of network interface cards, control devices, cables, and software required to create an Ethernet network.

Wireless data communications refers to telecommunications that take place over the air for data and Internet access.

Wireless Data Communications

Wi-FiWiMAXLong Term Evolution (LTE)

Concepts > Telecommunications > Wireless Data Communications

In this section:• Bluetooth• RFID• GPS

Wi-Fi (wireless fidelity) is networking technology that uses access points to wirelessly connect users to networks within a range of 250–1000 feet (75–300 meters).

Concepts > Telecommunications > Wireless Data Communications > Wi-Fi

Areas around access points where users can connect to the Internet are called hotspots.

Positioning access points at strategic locations throughout a building, campus, or city, Wi-Fi users can be continuously connected to the local area network (LAN) and Internet, no matter where they roam on the premises.

Wi-Fi

WiMAX, which stands for Worldwide Interoperability for Microwave Access (aka IEEE 802.16) is a so-called fourth-generation wireless broadband technology that evolved from Wi-Fi to provide faster Internet access at a longer range.

Concepts Telecommunications > Wireless Data Communications > WiMAX

WiMAX

WiMAX is being proposed as a solution to the “last mile” problem. The last mile refers to the part of a telecommunications network that connects to residences and businesses—the part of the network other than the backbone.

BluetoothBluetooth enables a wide assortment of digital devices to communicate directly with each other (in pairs) wirelessly over short distances.

A number of cell phone viruses have spread through Bluetooth. An open Bluetooth connection on a computer can be used by a hacker to access files on the computer. KEEP IT OFF, WHEN NOT IN USE.

Concepts > Telecommunications > Wireless Data Communications > Bluetooth

• PCs• Printers• Keyboards and

mice• Headphones and

headsets• Speakers• Mobile phones

• Digital cameras• MP3 players• Automobiles• Microwave

ovens• Refrigerators• Washers and

dryers

Some Bluetooth-Enabled Devices:

RFIDRFID, or radio frequency identification, uses tiny transponders in tags that can be attached to merchandise or other objects and read wirelessly using an RFID reader, typically for inventory management to facilitate commercial transactions.

Privacy advocates concerned that RFID could be used by governments and law enforcement agencies in ways that infringe on people’s privacy and civil liberties.

Concepts > Telecommunications > Wireless Data Communications > RFID

A GPS, or global positioning system, uses satellites to pinpoint the location of objects on earth.

Concepts > Telecommunications > Wireless Data Communications > GPS

GPS

GPS receivers provide navigation assistance and are also playing a part in social networking. Geotagging is the process of adding geographic identification metadata to digital media and messages.

Pager

A pager is a small, lightweight device that receives signals from transmitters for the purpose of communications and messaging.

Concepts > Telecommunications > Cellular Network > Pager

On-site paging systems are finding a variety of uses in businesses and organizations, including restaurants and emergency rooms.

National and regional systems set up transmission towers, much like cell phone networks, to cover large geographic areas.

A computer network is a collection of computing devices connected together to share resources such as files, software, processors, storage, printers, and Internet connections.

Computer Networks

Personal Area Network (PAN)Home Network

In this section:

Concepts > Telecommunications > Computer Network

• Local Area Network (LAN)• Wide Area Network (WAN)

Computer Networks• Devices attached to a network are called nodes.

Personal computers attached to a network are often called workstations.

• Local resources are files, drives, printers or other peripheral devices connected directly to the workstation. Remote resources are resources that the workstation accesses over the network.

• A system administrator is a person responsible for setting up and maintaining the network, implementing network policies, and assigning user access permissions.

• Networks are classified by size in terms of the number of users they serve and the geographic area they cover.

Personal Area network (PAN)

Concepts > Telecommunications > Computer Network > Personal Area Network (PAN)

A personal area network (PAN) is the interconnection of personal information technology devices, typically wirelessly, within the range of an individual.

Bluetooth technology allows personal devices to communicate without wires, sharing data, media streams, phone conversations, and all types of information.

A personal area network (PAN) typically covers a range of around 33 feet or 10 meters.

Home NetworkA home network is a local area network designed for personal or business use in the home.

Concepts > Telecommunications > Computer Network > Home Network

Home networks allow users to: • Share a single Internet connection • Share a single printer • Share files• Back up important files to another PC• Participate in multiplayer games • Stream music and movies from a

computer to devices around the house

Local Area Network (LAN)

A local area network (LAN) is a privately owned computer network that connects computers and devices within the same building or local geographic area.

Concepts > Telecommunications > Computer Network > Local Area Network (LAN)

In an intranet, a Web server provides confidential data to LAN users, while keeping the data safe from those outside the organization through the use of a firewall.

Virtual Private Network (VPN)A virtual private network (VPN) is a network that uses primarily public telecommunication infrastructure, such as the Internet, to connect an organization’s networks dispersed around the world into one large intranet.

Content can be extended to specific individuals outside the network, such as customers, partners, or suppliers, in an arrangement called an extranet.

Concepts > Telecommunications > Computer Network > Wide Area Network

VPNs typically require remote users of the network to be authenticated, and often secure data with encryption technologies.

Wide Area Network (WAN)A wide area network (WAN) connects LANs and MANs between cities, across a country, and around the world using microwave and satellite transmission or telephone lines.

Concepts > Telecommunications > Computer Network > Wide Area Network

A LAN becomes a WAN when it extends beyond one geographic location to another geographic location.

A WAN that crosses an international border is considered a global or international network.