GLOSSARY OF TERMS
Analog
Telephone transmission and/or switching which is not digital,
and which therefore is not represented in discrete terms such
as voltage on/off or light pulse on/off.
Anonymous FTP
Using the FTP function of the Internet without a secret login
ID and password. This is permitted on large systems that share
some of their files with outside users who otherwise would
not be able to login.
Asymmetric
Indicates there is an appreciable difference in the data rate
between the two directions of a transmission.
ATM
Asynchronous Transfer Mode. This high-speed network protocol
is composed of 53 byte "cells" having 5 byte headers
and 48 byte payloads. Because of its short packet length,
it is especially good for real time voice and video.
Audio
Audio transmission over a data network. The term implies a
one-way transmission to the listener, in which both the client
and the server cooperate for uninterrupted sound. (See Streaming
Video)
Bandwidth
This is the reflection of the capacity of a given transmission
channel. The greater the bandwidth the more information that
can be transferred over that network at one time.
BRI – Basic Rate Interface
There are two interfaces in ISDN: BRI and PRI (Primary Rate
Interface). In BRI, you get two bearer B-Channels at 64 kbps
and a data D-Channel at 16 kbps. The bearer B-Channels are
designed for PCM voice, video conferencing, group 4 facsimile
machines, or whatever you can squeeze into 64,000 bits per
second full duplex. The data D-channel is for bringing in
information about incoming calls and taking out information
about outgoing calls. It is also for access to slow speed
data networks, like videotext packet switched networks, etc.
SEE ISDN FOR BROADER EXPLANATION.
Bridge
A LAN (Local Area Network) Internet networking device that
filters and transfers data packets between LANs, enabling
them to operate as a single network.
Broadband
In general, broadband refers to telecommunication in which
a wide band of frequencies is available to transmit information.
Because a wide band of frequencies is available, information
can be multiplexed and sent on many different frequencies
or channels within the band concurrently, allowing more information
to be transmitted in a given amount of time (much as more
lanes on a highway allow more cars to travel on it at the
same time). Related terms are wideband (a synonym), baseband
(a one-channel band), and narrowband (sometimes meaning just
wide enough to carry voice, or simply “not broadband”, and
sometimes meaning specifically between 50 cps (characters
per second) and 64 kbps).
Carrier Access Code
CAC - A dialing code used to select a carrier
Cache
Local storage on your computer that holds in memory recently
viewed web pages. This allows you to review these pages quickly
without waiting for them to download from the Internet again.
Competitive Local Exchange Carrier
CLEC
A term for the deregulated, competitive telecommunications
carrier envisioned by the Telecommunications ACT of 1996.
Xfone, Inc. is a CLEC, along with ITCDeltacom, Network Telephone,
and a few others in this market.
Central Office
CO. 1. A physical building where subscribers’ lines are joined
to switching equipment for connecting other subscribers to
each other, locally and long distance. 2) A wire center in
which there might be several switching exchanges. 3) A simple
telephone switch, what the Europeans call a public exchange.
Collocation
Evolved from the Telecommunications Act of 1996. A Competitive
Local Exchange Company (CLEC) can locate its switches within
an Incumbent Local Exchange Carrier’s (ILEC) central office.
An ILEC is the dominant phone carrier within a geographic
area. There are basically two types of collocation, adjacent/physical
and virtual. Adjacent and physical are the same thing. XFONE
Inc. physically collocates in the Telcove Central Office (on
Harding Street, in Jackson MS). BellSouth brings their facilities
into Telcove’s Central Office, and Xfone
brings our facilities into the Telcove Central office, thereby
cross connecting in the Telcove Central Office. In other words,
Xfone’s equipment sits in the same
building as Telcove’s, in a locked cage. Only Xfone
personnel have the key. Access to that equipment is limited
ONLY to Xfone personnel, and is
24x7 because we must maintain it for customers who expect
service 24 hours a day seven days a week.
Connectivity
The ability to communicate between computers and terminals.
Constant Bit Rate (CBR)
CBR network traffic is a fixed amount of bandwidth. CBR is
consistent, both upstream and downstream. It is a dedicated
2-way connection.
Customer Premises (or Provided) Equipment
CPE. A wide range of customer-premises terminated equipment,
which is connected to the local telecommunications network.
This includes telephone, modems, terminals, routers, settop
boxes, etc.
Competitive Service Provider
CSP. A general term for all companies competing to deliver
telecommunications service to companies and individuals. The
term includes Regional Bell Operating Company’s (RBOC’s),
Competitive Local Exchange Carriers (CLEC’s), Interexchange
Carrier’s (IXC’s), and Incumbent Local Exchange Carrier’s
(ILEC’s).
Dedicated Line
A telephone or other communications line used for one purpose.
Demarc
The point at which Bell’s equipment stops and Xfone's
starts.
Demulitplex
To separate two or more signals previously combined compatible
multiplexing equipment.
Dial-up
A means of connecting to the Internet or any other computer
via a modem.
Digital
In displays, the use of digits for direct readout. In telecommunications,
digital is the use of a binary code to represent information.
Analog signals – like voice or music – are encoded digitally
by sampling the voice or music analog signal many times a
second and assigning a number to each sample. Recording or
transmitting information digitally has two major benefits.
First, the signal can be reproduced precisely. In a long telecommunications
transmission circuit, the signal will progressively lose its
strength and progressively pick up distortions, static and
other electrical interference “noises”.
In analog transmission, the signal, along with all the garbage
it picked up, is simply amplified. In digital transmission,
the signal is first regenerated. It is put through a little
“Yes-No” question. Is this signal a “one” or a “zero?” The
signal is reconstructed (i.e. squared off) to what it was,
identically. Then it is amplified and sent along its way.
So digital transmission is much “cleaner” than analog transmission.
The second major benefit of digital is that the electronic
circuitry to handle digital is getting cheaper and more powerful.
It is the stuff of computers. Analog transmission equipment
doesn’t lend itself to the technical breakthroughs of recent
years in digital.
Direct Outward Dialing
DOD. The ability to dial directly from an extension without
having to go through an operator or attendant.
Domain Name
A registered name that is given to an Internet address so
that the address is easy to remember. Before you can use a
custom domain name for your company, you must first register
your name. You may access www.internic.net for a list of certified
domain name registrars.
Domain Name Server
DNS. A computer on the Internet that contains the programs
and files that make up a domain’s name database. Using a name
server is much like placing a call to an 800-voice telephone
number. The number requires a “dip” into a database in order
to translate the name.
Domain Name Service
DNS. The name resolution service for IP addresses that provides
the text-based addresses for Internet resources. For example,
DNS enables a server with the IP address of 182.255.109.6
to be found on the Internet as www.---.com. The DNS provides
the protocol that allows clients (your computer) and servers
(the Internet) to communicate with each other.
Download
To receive a file transmitted over a network.
Downstream
Identifies the data rate from the exchange to the end-user.
Digital Signal, level 0
DS0. A hierarch of digital speeds used to classify capacities
of digital lines and trunks. DSO speed is 64 kbps.
Digital Signal, level 3
DS3. The equivalent of 28 T-1 channels, operating at a signaling
rate of 44.736 mbps.
Digital Subscriber Line
DSL . An industry acronym for Digital Subscriber Line technology
that delivers high-speed Internet access. Using your existing
telephone line, it delivers download speeds of up to 50 times
faster than 28.8K modems. The service lets you send data and
voice over the same line, at the same time so you can talk
or fax while you access the Internet.
Asymmetric Digital Subscriber Line
ADSL. (A) Uses existing UTP (Unshielded Twisted Pair)(A Pair
of wires that is twisted, so as to minimize crosstalk with
other pairs of wires in the same cable (which are each twisted
a t a slightly different rate) but not shielded.) copper wires
from the telephone company central office to the subscriber’s
premises. (B) involves electronic equipment in the form of
ADSL modems at both the central office and the subscriber’s
premises, (C) sends high speed digital signals up and down
those copper wires, and (D) sends more information one way
than the other – hence the term “asymmetric”. The original
speed specs for ADSL were T-1 (1.536 mbps) downstream from
the carrier to the subscriber’s premises and 16 kbps upstream.
Single Pair Symmetrical Services
SDSL. Offers digital bandwidth of up to 2.3 mbps both ways
(that’s why it’s called symmetrical) over a single twisted-pair
copper phone line, over distances up to about 10,000 feet
on an unrepeatered basis. SDSL is aimed at the corporate markets
that require high upstream and downstream traffic rates.
DSLAM
Digital Subscriber Line Access Multiplexer. The equipment
in your Central Office that provides your DSL Service connection
from your telephone line to Xfone
Internet service.
Dynamic IP
A Dynamic IP is an Internet Protocol address that changes
periodically. A different IP address may be assigned every
time you connect to the Internet. This makes it more difficult
for others to locate your computer or other device from elsewhere
on the Internet.
Ethernet
A LAN (Local Area Network) technology that operates over twisted-pair
wiring or coaxial cable speeds up to 100 Mbps or higher.
Ethernet Card
A printed circuit board that plugs into a computer to permit
the computer to connect to a network.
Ethernet Modem
An external modem that connects to your computer through an
Ethernet port or a Network Interface Card (NIC). This type
of modem enables home networking and is compatible with IBM
and Mac.
E-mail Address
The domain based address by which a user is referred to.
EndPoint
A network element at the end of the network. Either an originator
or a transmitter. A telephone would be an endpoint.
Fiber Optic
Made of very pure glass. Digital signals, in the form of modulated
light, travel on strands of fiber for long distances. Fiber
carries far more information than copper, over much longer
distances.
Filters
Filters are used to reduce interference on your
telephone devices from the digital signal provided by
the XDSL Service. Line filters are used with desktop
telephones as well as all other analog devices (i.e. fax
machines and Caller ID devices). Wall mounted filters
are used for telephones mounted to the wall (i.e.
kitchen phones). NOTE: Please keep in mind that a
maximum of 10 filters may be placed on your telephone
line. Installing more than 10 filters on your line will
cause interference and may affect your XDSL Service.
Firewall
A security device (hardware or software) that controls
access from the Internet to a local network by using
identification information.
FTP
File Transfer Protocol. The basic Internet function that
enables files to be transferred between computers. You
can use it to download files from a remote host
computer, as well as to upload files from your computer.
Integrated Access Device
IAD. A device that supports voice, data and video
information streams over a single, high-capacity
circuit.
Incumbent Local Exchange Carrier
ILEC. The dominant phone carrier within a geographical
area, as determined by the FCC.
InterLATA
Services, traffic or facilities that originate in one
LATA, crossing over and terminating in another Local
Access and transport Area. This can be either Interstate
of Intrastate service, traffic or facilities.
IntraLATA
Telecommunications services that originate and terminate
in the same Local Access and Transport Area. This can be
either Interstate or Intrastate service, traffic or
facilities.
Internet Protocol
IP. The Internet Protocol is a standard describing
software that keeps track of the internet’s addresses
for different nodes, routes outgoing messages, and
recognizes incoming messages. An IP address enables a
computer to be identified on the Internet while the user
is online.
IP Address
IP Addresses are numbers used to identify a specific
location on the Internet, much like a phone number is
used to identify a specific location on a telephone
network. Every device connected to the Internet has a
unique IP Address. For instance, a Web site such as
www.---.com would be assigned a unique numeric IP
address (222.222.22.222), much like your business has a
unique phone number (222-222-2222). When a user types
www.---.com into their browser, the software goes to an
Internet directory, finds that the Web site "lives" at
IP Address 222.222.22.222, and connects to that address
over the World Wide Web.
Integrated Services Digital
Network
ISDN
Basic Rate Interface
BRI. 144,000 bits per second and designed for the desktop. BRI
used to be a wonderful service in your home or office (it’s
been superseded by DSL and cable modems). BRI is useful if you
cannot get DSL or cable modem service, because it can be used
for videoconferencing and faster data communications. But it
is not an easy service to get up and running. With Xfone's
ability to offer dedicated internet access via T-1’s, in most
instances, we can increase the customer’s speed and DECREASE
monthly expenditures.
Primary Rate Interface
PRI. 23 B+1D Channel, or 1,544,000 bits per second,
which can be made into as many as 24 phone calls. PRI is
designed for telephone switches, computer telephony and
voice processing systems. This is a standard T-1 Line
which operates on two pairs.
Interexchange Carrier
IXC. Long-haul long distance carriers. IXC’s include all
facilities-based inter-LATA carriers. The largest IXC’s
are AT&T, MCI, Sprint and Worldcom; a huge number of
smaller, retgional companies also fit this definition.
The term generally applies to voice and data carriers,
but not to Internet Carriers. IXC is in contract to LEC
(Local Exchange Carriers). IXC’s also provide intraLATA
toll service and operate as CLEC’s in many states.
Internet Service Provider
ISP. An organization that provides access to the
Internet.
Java
A programming language that permits Internet sites on
the World Wide Web to include computer applications that
run on the computers of people who visit their sites.
Key Telephone Systems
KTS. A system in which the telephones have multiple
buttons. Since the KTS is not a switch, the user is
required to directly select central office phone lines
and intercom lines. Key Telephone Systems generally and
traditionally find most appropriate application in
relatively small business environments, typically in the
range of 50 telephones and requiring relatively
unsophisticated functionality and feature content.
Local Area Network
LAN. A short distance data communications network
(typically within a building or campus) used to link
computers and peripheral devices under some form of
standard control.
Last Mile
Not to be taken literally. “Last mile” is an imprecise
term that typically means the link – usually twisted
pair – between an end-user and the telephone company
central office – local, long distance or internet. Of
course, it doesn’t mean a “mile,” since that “mile”
could be less than a mile or several miles. The term has
entered the language referring to the problems of your
communications taking it that last mile. Often, that
last mile is runs over old, limited bandwidth copper
wire that has been in the ground for eons and is
supplied by a sleepy phone company who doesn’t have any
competition and not much incentive to perform and hasn’t
improved the quality of the cable in the loop. The vast
majority of local loops are less than 12,000 feet in
length – a little over two miles. Generally provisioned
with twisted-pair cable plant intended to support
voice=grade analog service, the “last mile” is the
source of much difficulty for high-speed data services.
Local Access and Transport Area
LATA. Also called Service Areas by some Bell Operating
Companies. One of 196 local geographical areas in the US
within which a local telephone company may offer
telecommunications services – local or long distance. At
one stage, ATYT was expressly prohibited from offering
IntraLATA calls by the terms of the Divestiture. But it
is now allowed to offer intraLATA phone calls. Other
competitors, such a MCI and Sprint, though rules vary by
state, have always been allowed to offer intraLATA phone
calls and do so in many states. LATA’s serve basically
two purposes. First, they provide a method for
delineating the area within which the Bell Operating
Companies may offer service. Second, they provided a
basis for determining how the assets of the former Bell
System were to be divided between the BOC’s and AT&T.
Metropolitan Area Network
MAN. A high-speed data intra-city network that links
multiple locations within a campus, city or LATA.
Modem
A device that adapts a computer to a telephone line. It
converts the computers digital pulses into audio
frequencies (analog) for the telephone system and
converts the frequencies back into pulses at the
receiving side.
Multiplexer
MUX. Electronic equipment, which allows two or more
signals to pass over one communications circuit.
Network Access Register
NAR. Centrex term describing a Central Office register
which is required in order to complete a call involving
access to the network outside the confines of that
Centrex CO. NAR’s may be incoming, outgoing or two-way.
NAR’s may be defined in support of local, intraLATA or
interLATA traffic. The specifics of NAR implementation
vary by Centrex provider.
Network Address Translation (NAT)
Network Address Translation is an Internet standard that
allows your local network to use private IP addresses,
which are not recognized on the Internet therefore
providing increased security.
Network Interface Card
NIC. An internal PCI card used to provide connectivity
to networked devices. XDSL uses an Ethernet NIC to
connect the personal computer to the ADSL modem (or to
the jack itself in some locations).
Network Interface Device
NID. A device that terminates copper pairs from the
serving central office at the user’s destination and
which is typically located outside that location. It
also provides an interface and demarcation point between
the network and customer premises equipment.
PCI Modem
An internal DSL modem that connects to your computer
through an open PCI slot and enables high-speed internet
access.
Peripheral Component Interconnect
PCI. Your PC may have one or more PCI slots available
for use with XDSL service. One of your available PCI
slots may be used to install an internal DSL modem to
connect directly with XDSL Service. Alternatively, a
Network Interface Card (NIC) may be installed in the PCI
slot to connect with XDSL via an external DSL Ethernet
modem.
Private Branch Exchange (Phone System)
PBX. A private (you, as opposed to the telephone company
owns it) branch (meaning it is a small phone company
central office) exchange (a central office was
originally called a public exchange, or simply an
exchange). In other words, a PBX is a small version of
the phone company’s larger central switching office. In
the very old days, you called the operator to make an
external call. Then later, someone made a phone system
that you simply dialed nine (or another digit), got a
second dial tone and dialed some more digits to dial
out, locally or long distance. So the Private Branch
Exchange of the early days (which needed an operator)
became Private AUTOMATIC Branch Exchange (which didn’t
need an operator). Now, all PBXs are automatic.
There are two alternatives to getting a PBX. You can
buy the newer, open more full-featured version called a
communications server. Or you can subscribe to your
local telephone company’s Centrex service.
Benefits of PBX:
a. Ownership. Once you’ve paid for it, you own it.
b. Flexibility. PBX is far more flexible than Central
Office based Centrex. PBX has more features and you can
change them faster. You can expand faster. Drop another
card in, plug some phones in, do your programming and
you’re live.
c. PBX phones. Electronic phones, often with screens and
dedicated buttons. They’re usually a lot easier to work.
A lot easier to transfer a call, conference another,
etc. A lot more productive.
d. Footprint Savings. Modern PBX’s take up room, more
than Centrex, but the space they take us if far less
than it used to be.
e. Voice Processing/Automated Attendants.
f. Open Architecture.
g. Good Reliability. There have been sufficient central
office crashes and sufficient improvement in the
reliability of PBX’s.
Point of Presence
POP. A long distance carrier’s office in your LATA. The
place your IXC terminates your long distance lines or to
your own direct hookup. Each IXC can have multiple POPS
within one LATA. All long distance phone connections go
through the POP’s.
POP3
Post Office Protocol. An Internet protocol that enables
a single user to read e-mail from a mail server.
POTS
Plain Old Telephone Service. POTS refers to a single
line, measured or flat rate, telephone service that
could be used as either a business line or residence
line.
PPPoA
Point to Point over Asynchronous Transfer Mode.
Professional Install
When placing your XDSL order, you may request a professional
installation by a Xfone authorized
technician. The professional installation may include any of
the following items (if required): phone line splitter and a
reasonable amount of wiring and cabling materials. The Xfone
XDSL installer will be responsible for installing either a Xfone
purchased DSL modem to a single computer, or a Xfone
purchased DSL router for up to two standalone computers or a
LAN. Xfone can configure additional
computers for an additional charge or leave instructions for
configuration of additional computers to your router. The Installer
may provide up to two Network Interface Cards (NIC), if needed,
with our router package. If necessary, additional NIC cards
may be purchased at a retail store that sells networking devices.
RBOC
Regional Bell Operating Companies.
Residential Gateway
A device that terminates one or more external network(s),
provides and enhances access to the Internet and
distributes service(s) via an in-home network.
Router
An interface between two networks. It acts as a
switching office for networks.
Self-install
A self-install option is available for XDSL. After you
place your order, we will activate XDSL on your business
telephone line and ship your modem or router kit to your
business. When your kit arrives, simply install your
modem or router hardware and software using our
step-by-step instruction guide. Support is available if
assistance is needed.
Server
Hardware definition. A shared computer on the
local area network that can be as simple as a regular PC
set aside to handle print request to a single printer.
More usually, it is the fastest PC around that may be
used as a repository and distributor of data. It may be
the gatekeeper controlling access to voicemail,
electronic-mail, facsimile services. At one stage a
local area network had only one server. Today, networks
have multiple services. Servers today have multiple
brains, large arrays of big disk drives (often in
redundant arrays) and other powerful features.
Software definition. A program which provides
some service to other client programs. The connection
between a client program and the sever program is
traditionally by message passing, often over a local
area or wide area network, and uses some protocol to
encode the client’s requests and the servers responses.
Any given program may be capable of acting as both a
client and a server, perhaps switching its role base on
the nature of the connection. The terms client and
server simply refer to the role that the software
program performs during a specific connection.
SONET
Synchronous Optical Network. A family of fiber optic
transmission rates from 51.84 million bits per second to
13.27 gigabits (thousand million) per second, created to
provide the flexibility needed to transport many digital
signals with different capacities, and to provide a
design standard for manufacturers.
Static IP
A Static IP Address is a "fixed" IP address assigned to
a specific computer or other device on a network. The IP
address remains the same and is associated with that
computer or device.
IP Addresses are numbers used to identify a specific
device connected to the Internet, much like a phone
number is used to identify a specific telephone. An IP
address is organized into four groups of numbers
separated by periods, or dots, such as 204.32.345.61.
Every device connected to the Internet has a unique IP
Address. For instance, a Web site such as
www.johnsmith.com would be assigned a unique numeric IP
Address (192.168.70.10). When a user types
www.johnsmith.com their browser, the software goes to an
Internet directory, finds that the Web site "lives" at
IP Address (192.168.70.10), and connects to that address
over the World Wide Web.
Switch
An assembly of equipment arranged for establishing
connections between lines, lines to trunks, or trunks to
trunks.
T-1
A digital transmission link with a total signaling speed
of 1.544 mbps.
T-3
A digital transmission link with a total signaling speed
of 44.736 mbps, equivalent to 28 T-1’s.
Twisted Pair
Two insulated copper wires twisted around each other to
reduce interference from one wire to another.
UNE
Unbundled Network Element. A term used in
negotiations between a CLEC and the ILEC to describe
various network components that will be used or leased
by the CLEC form the ILEC. These components include such
things as the actual copper wire to the customer, fiber
strands, and local switching.
Streaming Video
Video transmission over a data network. The term implies
a one-way transmission to the viewer, in which both the
client and the server cooperate for uninterrupted sound.
(See Streaming Audio
UBR
Unspecified bit rate.
Upstream
Identifies that data rate from the end-user to the
exchange.
URL
Uniform Resource Locator. This is the equivalent of
having the phone number of a place you want to call. It
identifies the protocol, host name and file name of the
Internet resources you want, such as Web pages and FTP
sites.
USB
Universal Serial Bus. A "plug and play" interface
between a computer and add-on devices (such as audio
players, joysticks, keyboards, telephones, scanners, and
printers). With USB, a new device can be added to your
computer without having to add an adapter card or even
having to turn the computer off. The USB peripheral bus
standard was developed by Compaq, IBM, DEC, Intel,
Microsoft, NEC, and Northern Telecom and the technology
is available without charge for all computer and device
vendors.
USB Modem
An external DSL modem that connects to your computer
through an open USB port and enables high-speed Internet
access. This type of modem enables a plug and play
environment.
USB Port
Universal Serial Bus. Your computer may have one or more
USB ports available for use with XDSL service. One of
your available ports may be used to connect to a DSL USB
modem.
Wide Area Network
WAN. A computer and voice network bigger than a city or
metropolitan area.
Web Hosting
A service performed by Internet Service Providers
(ISP’s) and Internet Access Providers (IAP’s) who
encourage outside companies to put their Web Sites on
computers owned by the ISP’s.
XDSL
Xfone with DSL access with speeds
up to 1.5 Mb downstream and 256K upstream. This service is provided
with a Dynamic IP address. XDSL is used for high-speed Internet
access that will allow you to search the Web and download large
files up to 50 times faster than with a 28.8K modem.
XDSL Static IP
Xfone with DSL access with speeds
up to 1.5 Mb downstream and 256K upstream. This service is provided
with single or multiple Static IP and Domain Name Service (DNS).
XDSL Static IP is often used for remote access to a Local Area
Network (LAN) or a Virtual Private Network (VPN), hosting a
Web server (such as www.---.com), a file transfer protocol (FTP)
server, an e-mail server or other applications server.
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