CIS 105 Survey of Computer Information Systems

CIS 105 Concepts and Terminology Unit 9

CIS 105

Survey of Computer Information Systems

Essential Concepts and Terminology

Study Unit 9


Telecommunications. The process of sending information

of any kind over telephone lines.


Public Switched Telephone Network (PSTN).

The technology enabling direct and almost instantaneous connections between any of nearly one-half billion telephones world-wide.


Local Exchange Carriers (LEC).

Telephone services which provide direct, wired connections between subscribers without accessing long-distance carriers. Also known as local access and transport areas (LATA).


Analog Telephone. A device that transmits a

continuously varying signal matching the acoustics of the human voice.


Subscriber Loop Carrier (SLC).

A telephone system installation that connects as many as 96 subscribers (a local loop) to a local exchange. The SLC may transform local analog signals to digital signals before transmission to the local exchange.


Interexchange Carrier (IXC).

A long-distance telephone company.


Bandwidth. The data transmission capacity of

a communications channel. The bandwidth of a digital signal is measured in bits per second (bps); of an analog signal in Hertz.


T1 Carrier. Specially conditioned copper wires

capable of transmitting 24 voice calls or 1.544 Mbps of data simultaneously.


Fiber-Optic Cable. A bundle of thin strands of glass

used to transmit data by means of pulses of light.


T3 Carrier. A fiber-optic cable capable of

transmitting 672 voice calls or 43 Mbps of data simultaneously.


Microwaves. An electromagnetic wave with a

frequency of at least 1 gigahertz. High-frequency radio waves requiring line-of-sight transmission.


Wireless Networks. Networks that use radio or infrared

signals (instead of cables) to transmit data from one network device to another.


Cell Sites. A network of automatic repeating

transmitters which broadcast a signal throughout a limited geographic are (a cell).


Mobile Telephone Switching Office (MTSO).

The technology connecting cell sites and connected to the standard PSTN telephone system.


Modem. A device that transforms digital

signals into analog form and vice-versa. Modems send and receive data to and from computers over telephone lines.


Modulation. The process of changing the

characteristics of a signal (for example, when a modem changes a digital pulse into an analog signal).


Modulation Protocols. Rules set by international

standards organizations to ensure that modem made by different manufacturers can communicate correctly.


Integrated Services Digital Network (ISDN).

A telephone company service that transports data digitally over dial-up or dedicated lines.


Basic Rate ISDN (BRI). Service offering one or two 64

Kbps channels. Two channel ISDN allows a 128 Mbps data transfer rate, and one channel of data transfer during voice calls.


Primary Rate ISDN (PRI). Service with 23 channels at 64

Kbps each and one signaliong channel, requiring a T1 carrier (1.544 Mbps).


ISDN Adapter. The digital connection between a

computer and an ISDN line, also called a digital modem (a misnomer).


Asymmetric Digital Subscriber Line (ADSL).

A type of DSL service for Internet access that enables download speeds of up to 1.5 Mbps.


Coaxial Cable. A type of high-bandwidth

connecting cable with an insulated center wire surrounded by a grounded shield of braided wire.


Cable Modem. A communications device that

delivers 0.5 to 1.0 Mbps or more of data, used to connect a computer to the cable TV infrastructure.


Digitization. The transformation of media into

digital data.


Broadband. A term used to refer to

communication channels that provide high bandwidth using multiplexing.


End of Study Unit 9. Return to first slide

Move to Study Unit 10

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CIS 105 Survey of Computer Information Systems

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