56K Line -
A digital phone line connection (leased line) capable of
carrying 56,000 bits per second. At this speed, a megabyte
will take about 3 minutes to transfer. The standard modem in
use today is the 56 Kbps dialup modem.
ADSL (Asymmetric DSL) -
ADSL offers differing upload and download speeds and can be
configured to deliver up to 6 Mbps from the network to the
customer ¬ that is up to 120 times faster than dialup
service and 100 times faster than ISDN. ADSL enables both
voice and high speed data to be sent simultaneously over
existing phone lines. This type of DSL is the most
predominant in commercial use for business and residential
customers around the world. ADSL is good for general
Internet access and for applications where downstream speed
is most important, such as video-on-demand.
Bandwidth -
The data transfer capacity of an electronic
communications system. When a measurement of bandwidth is
given, it primarily represents the maximum data transfer
rate of such a system measured in kilobits per second (Kbps)
or megabits per second (Mbps).
Baud -
Baud was the prevalent measure for data transmission
speed until replaced by a more accurate term, bits per
second (bits per second).
Bit -
A bit is the smallest unit of data in a computer. A bit
has a single binary value, either 0 or 1. In most computer
systems, there are eight bits in a byte.
BPS (Bits Per Second) -
In data communications, bits per second (abbreviated
bps) is a common measure of data speed for computer modem
and transmission carriers. As the term implies, the speed in
bps is equal to the number of bits transmitted or received
each second.
Byte -
In most computer systems, a byte is a unit of data that
is eight binary digits long. A byte is the unit most
computers use to represent a character such as a letter,
number, or typographic symbol (for example, "g", "5", or
"?").
DSL (Digital Subscriber Line) -
A technology that exploits unused frequencies on copper
telephone lines to transmit traffic at much higher speeds.
DSL can allow voice and high speed data to be sent
simultaneously over the same line. Because the service is
'always available,' end-users don't need to dial in or log
on to the Internet.
Ethernet -
Ethernet is the most widely-installed local area network
(LAN) technology. The most commonly installed Ethernet
systems are called 10BASE-T and provide transmission speeds
up to 10 Mbps.
Fire Wall -
A combination of hardware and software that separates a
LAN into two or more parts for security purposes.
HDSL (High Data Rate DSL) -
Available at 1.5 or 2.3 Mbps, HDSL does not provide standard
telephone service over the same line. It is seen as an
economical replacement for a T-1 line.
IDSL (Integrated Services Digital
Network DSL) -
Also called ISDN DSL. This is a form of DSL that supports
symmetric data rates of up to 144 Kbps using existing phone
lines. IDSL differs from its relative, ISDN, in that it is
an "always-available" service, but capable of using the same
terminal adapter, or modem, used for ISDN. Unlike true ISDN,
it's only for data. It can reach farther distances than ADSL
or SDSL.
IP Address -
A unique number consisting of four parts separated by dots.
For example: 123.45.678.9. Every machine that is on
the Internet has a unique IP number. If a machine does not
have an IP number, it is not really on the Internet.
ISDN -
Integrated Services Digital Network. Basically a way to move
more data over existing regular phone lines. ISDN is rapidly
becoming available to much of the USA and in most markets it
is priced very comparably to standard analog phone circuits.
It can provide speeds of roughly 128,000 bits per second
over regular phone lines. In practice, most people will be
limited to 56,000 or 64,000 bits per second.
Kilobit -
Approximately one thousand bits (1024 bits, to be
exact). Data transfer rates are measured in kilobits per
second, abbreviated as Kbps.
Kilobyte -
Approximately one thousand bytes (1024 bytes, to be exact).
While kilobits are used to measure data transfer, kilobytes
are used to measure memory capacity. Kilobyte is usually
abbreviated as K or KB. For example, 256K of RAM means a
computer has 256,000 bytes of Random Access Memory.
LAN (Local Area Network) -
A computer network limited to the immediate area, usually
the same building or floor of a building.
Leased-Line -
Refers to a phone line that is rented for exclusive 24-hour,
7-days-a-week use from your location to another location.
Many of the highest speed data connections will require a
leased line, such as T-1's and T-3's.
Megabit -
Approximately one million bits. Higher rates of data
transfer are measured using megabits per second, abbreviated
as Mbps.
Megabyte -
Approximately one million bytes. While megabits are used to
measure data transfer, megabytes are used to measure memory
capacity. Megabyte is usually abbreviated as M or MB. For
example, 200 MB of disk storage space on a web hosting
account means the account has 200,000,000 bytes of hard
drive space upon which to store its files.
Modem -
The term is taken from the first letters of "Modulator,
Demodulator". A modem is a device that you connect to your
computer and to a phone line that allows the computer to
talk to other computers through the phone system. Modems
convert the digital signal to analog so it can travel the
phone line and then back to digital again for processing.
NIC (Network Interface Card) -
A NIC is a computer circuit board or card that is installed
in a computer so that it can be connected to a network.
Personal computers and workstations on a local area network
(LAN) typically contain a network interface card
specifically designed for the LAN transmission technology,
such as Ethernet or token ring. Network interface cards
provide a dedicated, full-time connection to a network. Most
home and portable computers connect to the Internet through
as-needed dial-up connection. The modem provides the
connection interface to the Internet service provider.
PPP (Point to Point Protocol) -
A protocol that allows a computer to use a regular phone
line and a modem to make TCP/IP connection and thus be
really and truly on the Internet.
RADSL (Rate Adaptive DSL) -
A non-standard version of ADSL that adjusts dynamically to
varying lengths and quality of access lines. With RADSL, the
modem will test the line at start up and adjust its
operating speed to the fastest the line can handle.
SDSL (Symmetric DSL) -
SDSL is a vendor-proprietary version of DSL that can provide
the customer with speeds ranging from 128 Kbps to 2.32 Mbps.
SDSL offers the same upstream and downstream speeds, but it
can't share the line with voice communications.
T-1 Line -
A leased line connection capable of carrying data at
1,544,000 bits per second, or 1.544 Mbps. Generally, a T-1
line will move a megabyte of data in 10 seconds. That is
still not fast enough for full-screen, full-motion video,
for which you need at least 10,000,000 bits per second. T-1
is the fastest speed commonly used to connect networks to
the Internet.
T-3 Line -
A leased line connection capable of carrying data at
45,000,000 bits per second or 45 Mbps. This is more than
enough to do full-screen, full-motion video.
TCP/IP -
Stands for "Transmission Control Protocol / Internet
Protocol". TCP/IP is a suite of communications protocols
that forms the basis for and defines the Internet.
UADSL (Universal Asymmetric DSL) -
UADSL can deliver up to 1.5 Mbps downstream and 512 Kbps
upstream. Like ADSL, it's asymmetric and allows you to use
the same telephone line for both standard telephone service
as well as high speed Internet connectivity. With the speeds
that UADSL provides, it is intended primarily for consumers
rather than businesses.
URL (Uniform Resource Locator) -
The standard way to give the address of any resource on the
Internet that is part of the World Wide Web (WWW). A URL
looks like this:
http://www.lodgetel.com/
The most common way to use a URL is to enter into a WWW
browser program such as the Microsoft Internet Explorer or
Netscape.
VDSL (Very High Bit Rate DSL) -
A new type of DSL that is still in development, VDSL can
transmit in speeds up to 26 Mbps, over distances up to 50
Meters on short loops such as from fiber to the curb. The
highest speeds are currently obtainable at short distance
only.
WAN (Wide Area Network) -
A term referring to any Internet or network that covers an
area larger than a single building or campus.
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