Basics Of Isdn; What Is Isdn; What Does Isdn Have To Offer - Siemens I-SURF User Manual

3. Basics of ISDN

3.1 What is ISDN ?

ISDN is an abbreviation for Integrated Services Digital Network, a modern
communications network. ISDN lets you enjoy all the many facets of electronic
communications. You can surf the Internet, balance your accounts using home
banking services, or remotely connect to your company's computer network.

3.2 What Does ISDN Have to Offer?

The ISDN telecommunications network offers subscribers digital payload channels
(B channels) with a maximum transfer speed of 64 kbps. The most important
improvement of ISDN over conventional analog public communications networks is
that ISDN supports a variety of different types of telecommunications services.
ISDN connections are not limited to data, as is the case with some other network
types, but are equally suitable for carrying speech, text, or images.
This constitutes a tremendous economic advantage, since the same lines can be
used for speech, fax, or data communications as needed. Standard ISDN access to
Euro features 2 B channels and 1 D channel (for service and control purposes).
ISDN is unrivaled when it comes to dial-up connections:
Connections are established quickly (in approx. 1.8 seconds)
No handshaking process, unlike standard analog modems
Optimized use of resources
High transfer rate of 64 kbps per B channel
In addition to the B payload channels ISDN features a parallel service channel
called D channel. This channel is used to carry information on establishing and
terminating connections as well as data relevant to in-call control.
The subscriber line that the ISDN user is provided with is called basic access. Each
basic access offers two B channels with a bandwidth of 64 kbps each and a D
channel with a bandwidth 16 kbps.
B channels can either be used separately or combined for greater data transmission
bandwidth. The present ISDN terminal adapter thus offers its users flexible
bandwidth , provided that this channel combination feature (trunking) is supported
by the software used.
3. Basics of ISDN
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