Nortel Modular ICS 7.1, Инструкция по установке

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/ Welcome to ISDN
Modular ICS 7.1 Installer Guide N0130943 02
Systems with only U-LT and S loops act as timing masters for
the attached terminal equipment (TE), and are not
synchronized to the network. ISDN TE without access to a
network connection (BRI lines) has limited or no
functionality.
If your system has both a BRI and a DTI card configured as
PRI installed, it is recommended that you use PRI as the
primary clock source, see
DTI card configured as a PRI card
on page 64.
Other ISDN BRI equipment: NT1
The NT1 (network termination type 1) connects an S interface
(four-wire) to a U interface (two-wire). In most cases, it
connects loops from a BRI-ST card to the network connection,
which uses the U interface. It can also connect S interface
terminal equipment (TE) to the U loop from a BRI-U2 or
BRI-U4 Card.
An NT1 is not required to connect from the network to BRI-U
cards or to connect U interface TE to an ICS equipped with
BRI-U cards.
The NT1 converts and reformats data so it can be transmitted
to and from the S or T connection. In addition, it manages the
maintenance messages travelling between the network and the
NT1, and between the NT1 and the ICS.
The NT1 from Nortel Networks is packaged two ways:
• as a stand alone package, which contains one NT1 card
(NTBX80XX) and a power supply (NTBX81XX)
• as a modular package, which contains up to 12 NT1 cards
(NTBX83XX) and a power supply (NTBX86AA)