Eicon Networks 1550 - Manual (Page 125)

Web Interface Settings Glossary 125
Important ISDN Concepts
This section describes important ISDN concepts. Understanding these concepts will
help you decide how to choose the protocol for your Eicon 1551 for optimal
performance and cost savings.
ISDN channels ISDN lines are defined in terms of channels, with each channel
supporting a specific type of communication. The Eicon 1551
supports two ISDN channel types:
D-channel: The D-channel is used to control the setup of ISDN
connections on the B-channels. The D-channel has a transmission
speed of 16 kbps.
B-channel: B-channels are used to carry data or voice traffic and
have a transmission speed of 56 or 64 kbps.
ISDN access
interfaces An access interface is the physical connection between you and an
ISDN network. It defines the number of D- and B-channels that are
available to you and the total transmission speed of the connection.
The Eicon 1551 supports a single Basic Rate Interface (BRI),
which is comprised of one D-channel (16 kbps) and two
B-channels (64 kbps) for a total user bit rate of 144 kbps.
ISDN channel
usage All connections, both data and voice, are carried on the
B-channels. The Eicon 1551 dynamically assigns B-channels on
demand. Therefore, there is no guarantee which B-channel a
specific connection will receive. The same is true for your ISDN
phone numbers. Your first phone number does not necessarily map
to ISDN channel B1.