Nortel BCM50 2.0, Installation Manual

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Telephony Device Installation Guide
Chapter 5
ISDN overview
The following provides some general information about using ISDN lines on your BCM50 system.
Detailed information about ISDN is widely available through the internet. Your service provider
can also provide you with specific information to help you understand what suits your
requirements.
Refer to the following topics for information:
• "ISDN fundamentals"
• “Services and features for ISDN BRI and PRI” on page 31
• “ISDN hardware” on page 36
• “ISDN standards compatibility” on page 38
• “Planning your ISDN network” on page 39
• “Supported ISDN protocols” on page 40
ISDN fundamentals
Integrated Services Digital Network (ISDN) technology provides a fast, accurate and reliable
means of sending and receiving voice, data, images, text, and other information through the
telecom network.
ISDN uses existing analog telephone wires and multiplex it into separate digital channels which
increases bandwidth.
ISDN uses a single transport to carry multiple information types. What once required separate
networks for voice, data, images, or video conferencing is now combined onto one common
high-speed transport.
Refer to the following topics:
• “Types of ISDN service” on page 30
• “ISDN layers” on page 30
• “ISDN bearer capability” on page 31
Analog versus ISDN
ISDN offers significantly higher bandwidth and speed than analog transmission because of its
end-to-end digital connectivity on all transmission circuits. Being digital allows ISDN lines to
provide better quality signaling than analog POTS lines, and ISDN out-of band data channel
signaling offers faster call set up and tear down.
While an analog line carries only a single transmission at a time, an ISDN line can carry one or
more voice, data, fax, and video transmissions simultaneously.