Operation Manual

5
1 Introduction
1 Introduction
1.1 What is ISDN?
ISDN is the internationally standardized digital
telecommunications network. The abbreviation ISDN
stands for Integrated Services Digital Network.
ISDN has three outstanding features that make it diffe-
rent from conventional communications media:
Integration of Services
The first is the integration of services. This means that all
telecommunications services, such as telephony, telefax,
data communications or videotex, are carried over a
single data network. Voice, text, files and even images
can be transmitted over ISDN. Users can connect several
different terminals and use all available services with one
ISDN line. Because the basic-rate ISDN subscriber access
provides two user data channels (B channels), you may
use two different telecommunications services at the
same time—to receive a fax during a telephone
conversation, for example.
High Throughput
The second substantial feature is the extraordinary
speed of data transmission in ISDN. Voice and data are
transmitted over the BRI’s two B channels at the rate of
2 x 64,000 bits per second. Furthermore, the AVM
ISDN-Controller B1 USB allows ISDN applications to
bundle the two B channels so that throughput is doubled.
Outstanding Quality
The third important feature of ISDN is the end-to-end
digital transmission of user data: this is the basis for high
transmission quality. Poor connections, noise and
interference, which cause transmission errors or
interruptions in analog networks, are eliminated. Data
communication over ISDN is thus not only faster, but also
more reliable than in analog networks.