Isdn Technology; What Is It; How It Works - Zoom ISDN TA Owner's Manual

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Flash memory for code updates via software downloads.
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Simultaneous voice and data capability, with voice on one B-
channel and data on the other.
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This product may also include an optional telephone handset for
making or receiving voice calls over an ISDN line.

ISDN Technology

What Is It?

Integrated Services Digital Network (ISDN) is a technology that uses
digital transmission instead of analog transmission over standard tele-
phone lines. Among the many advantages of ISDN service are the fol-
lowing:
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ISDN's digital technology service provides faster and more reliable
data transfers.
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ISDN's connection and negotiation are much faster than with
analog modems. Typical connection time for an ISDN call is under
three seconds.
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ISDN's maximum high speed doesn't depend on line quality.
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ISDN's service allows you to connect to two different communica-
tions devices, such as a telephone and ISDN terminal adapter, at
the same time, while analog provides a single connection at a time.

How It Works

While both technologies use the same type of copper wire connection
between your house and the phone company, ISDN Basic Rate Interface
(BRI) service converts information flow into three channels, two B-
channels and one D-channel, referred to as 2B+D service. The two B-
channels have a bandwidth of 64 Kbps each. These two channels may
be used independently (for voice, fax, data or video), or they may be
bound together (bonded) to provide a single 128 Kbps connection.
Chapter 1 Introduction 7