- 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 Kbps 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.
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