| Q: |
What is ISDN?
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| A:
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ISDN stands for Integrated Services Digital Network. ISDN is a
high speed, high capacity digital communication line. Basic Rate
ISDN is comprised of 3 communications paths called channels. The
two primary channels communicate at 64 kilobits per second (kbps)
and the third at 16 kbps. The third channel is primarily used
for behind-the-scenes signaling.
ISDN can
be configured with virtually any of the features available with
a standard telephone line, such as Call Forwarding, Three Way
Calling, etc. However, it also has the capability to do things
not feasible with a standard line, such as Video Conferencing.
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| Q: |
Can I communicate with people and locations that don't have ISDN?
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| A:
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ISDN is designed to work smoothly with traditional telephone service.
Customers who subscribe to ISDN can make voice calls to and receive
voice calls from customers who subscribe to traditional telephone
service.
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| Q: |
How do I know if ISDN is available in my area?
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| A:
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There are 2 stages of qualification to determine if ISDN is available
at your location. The first stage is to verify that your serving
central office -- which provides telephone service to your locations
-- has ISDN capability. The majority of the central offices in
BellSouth territory are equipped with ISDN or can be "linked"
with a Central Office that is ISDN equipped.
The second
stage is to determine if your local loop is qualified. This
loop is the connection from the Central Office to your home
or business. If you live more than 3 miles from the central
office, you may not qualify, but we may be able to make special
arrangements to get ISDN to you. BellSouth is continually expanding
ISDN availability.
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| Q: |
What if
my central office does not have ISDN capability?
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| A:
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You still may be able to obtain ISDN service from a nearby central
office that is equipped with ISDN. There may be an additional
charge for both of these services.
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| Q: |
Will ISDN
work over my existing phone wires?
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| A:
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ISDN works over the copper wires that run to your location, but
it may require special jacks and connections. Some inside wiring
changes may also be required.
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| Q: |
Will ISDN
work with my existing equipment?
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| A:
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In almost all cases, ISDN requires special equipment. If connecting
ISDN to a PC, a terminal adapter (sometimes called an "ISDN modem")
is required. Many of the terminal adapters come with 1 or 2 standard
jacks (RJ-11), so standard (analog) phones and/or facsimile machines
can be connected. BellSouth has now made it easier than ever for
you to purchase ISDN equipment by forming alliances with ISDN
equipment manufactures and distributors. Also, this equipment
is often sold where PCs and PC equipment are sold.
If ISDN
is being used for voice applications, a special digital telephone
set may be desirable to take full advantage of many calling
features such as caller number identification. This equipment
is often sold in office supply stores and PC stores.
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| Q: |
Why is
ISDN better than a standard (analog) line with a modem?
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| A:
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If you transmit very large data files, ISDN provides speed and
capacity that may not be possible over an analog line, regardless
of the modem speed. For example, videoconferencing is difficult
over an analog line, but is close to full motion over ISDN. Many
terminal adapters have the capability to use both of the two 64
kbps channels to allow you to communicate at 128 kbps.
ISDN is
an end to end digital connection which provides cleaner data
and clearer voice. Analog telephone sets convert the sound waves
of your voice to analog electrical waves (analog transmission).
ISDN sets convert your voice into voltages representing a string
of 0s and 1s (digital transmission), similar to those on a compact
disc recording. In both cases, these converted electrical signals
are sent over the telephone network. However, as an analog transmission
travels through the telephone network, it can pick up noise
from power lines, moisture in telephone cables, lightning, or
crosstalk from other lines. These noise sources do not contaminate
ISDN transmission. Therefore ISDN sound quality and transmission
reliability is far better than traditional voice service.
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| Q: |
What is
the cost of ISDN?
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| A:
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The price varies depending on issues such as the configuration
you select, the minimum service period that you select, and the
state in which you are ordering the service.
Installation
charges vary by state and you may desire some wiring, additions
of jacks or relocation of existing jacks to ensure that the
service is installed where and how you can best use it. Visit
the "Price
ISDN For You" section for more information.
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| Q: |
Why is
it more expensive than a standard phone line?
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| A:
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ISDN is a very high-feature, high-speed, high-capacity and high-quality
communication line. It is comprised of two channels for communication,
giving it the functionality of two standard lines. In addition,
ISDN includes some features such as Caller ID, Call Waiting, and
Call Hold. Providing these capabilities is costly. But, remember
that ISDN will help improve your productivity through increased
speed, expanded applications (such as video conferencing and realtime
application sharing), and improved communications -- you know
when that important call is arriving.
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| Q: |
How competitive
is BellSouth ISDN pricing?
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| A:
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As is often the case when a technical service is first embraced
by a market, ISDN still has a wide variety of pricing plans available
across the nation. Just as we are beginning to see on-line service,
cellular and long distance prices begin to "settle down" and stabilize,
ISDN pricing will also. BellSouth rates are reflective of the
ISDN demand, customer usage in our region and the state and federal
regulations. You will continue to see pricing plans introduced
and withdrawn across the nation as ISDN grows in mass market appeal.
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| Q: |
Why is
it less expensive in Tennessee?
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| A:
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The residential rate for ISDN in Tennessee is approximately $20.
This is because ISDN is part of a larger technology program specific
to Tennessee where a "pool" of funds has been set aside to assist
(or supplement) customer rates on certain technology (which includes
ISDN). This rate has been set independent of the cost associated
with providing ISDN and can exist only because the technology
program covers the remaining costs.
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| Q: |
Is the
hardware associated with ISDN expensive?
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| A:
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Many ISDN hardware manufacturers have already lowered their prices
significantly. Similar to any new technology, such as VCRs and
personal computers, prices are often initially high, but come
down as more units are sold and economies of scale take place.
BellSouth does not manufacturer hardware for ISDN.
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| Q: |
Does ISDN need its own power back-up?
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| A:
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Traditional telephone sets receive electrical power from the copper
wires that link your home to the local central office. When there
is a power failure in your neighborhood, traditional telephone
service is not interrupted because backup generators in the Central
Office send power to your telephone over your line. ISDN requires
more power than your phone line can carry, so ISDN equipment must
be powered from electrical outlets in your home or business.
In the event
of a power failure, ISDN will not operate unless it has a power
back-up such as a Uninteruptable Power Supply (UPS). Just as
a PC requires power back-up in case of a power failure, ISDN
equipment may run off of the same back-up. Battery back-up is
available where PCs and PC equipment are sold.
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| Q: |
Should
ISDN be the only line to my location?
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| A:
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While this is a matter of choice, an ISDN line can serve as the
only phone line to your home and business -- if you have a backup
power supply (as mentioned above) in the event of a power failure.
You may want to keep your existing lines and add ISDN for specific
purposes that cannot be accommodated by your present line (e.g.,
higher transmission speed).
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| Q: |
Who do
I call for more information?
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| A:
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Call the BellSouth Regional ISDN Center: 1-800-858-9413
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| Q: |
Glossary of Terms
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| A: |
Channel: A channel is a communication path that can carry
a voice or data conversation. ISDN has multiple channels [a maximum
of two (2) "B"s and one (1) "D".]
B Channel:
This is an ISDN communication channel that bears or carries
voice, circuit-switched data, or packet-switched data conversations.
D Channel:
This is an ISDN communication channel used for sending information
behind-the-scenes between the ISDN equipment and the ISDN central
office switch. This channel can also carry "user" packet data
at rates up to 9.6 kilobits.
Circuit
Switched Data: A conversation between two devices (usually
computers) where the devices have total use of the channel connecting
them.
Packet
Mode Data: In this type of conversation between two devices
(usually computers), each device's "dialogue" is broken into
small chunks called packets before being sent to the receiver.
Unlike voice and circuit switched data calls, one communication
channel can carry multiple packet conversations at the same
time.
SPID:
The ISDN central office needs to have a unique identification
number for each ISDN set to which it sends calls and signals.
This identification is called a Service Profile Identifier or
SPID.
NT1:
The NT1 (network termination 1) is a user owned device that
provides an interface between your line from the telephone company
and the ISDN wiring inside your home. This device can be a stand-alone
device or can be integrated with other ISDN equipment. Your
ISDN service will not work if the NT1's plug is not connected
to a working electrical source.
Signaling:
Your central office knows that you wish to make, take, or interrupt
a call when it receives special signals from picking up a handset,
dialing, depressing buttons on your set, etc. Before ISDN, you
frequently had to interrupt or terminate your conversation to
signal the central office. ISDN lets you talk and signal at
the same time.
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