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CHAPTER 2: Introduction
2. Introduction
2.1 Description
The Network Termination Device (NTU-1) is designed for the ISDN basic rate
communication system. It installs between the Central Office U interface, and the
customer premise S or T interface. It effectively converts the central office 2-wire
echo-canceled 2B1Q code to a customer premise 4-wire alternate space inversion
code (see Figure 2-1). Both point-to-point and multipoint configurations are
supported.
Figure 2-1. Typical ISDN interface arrangements.
The NTU-1 can reside on a desk or be wall mounted. Six light-emitting diodes
(LEDs) show unit status. The rear panel houses the power jack, two jacks for either
an S or T interface to the customer premise equipment, one U jack for connection
to the central office, and one 4-position DIP switch for terminating resistor
selection. Power is supplied by the wall transformer, which also provides power to
the associated terminal devices via the S/T jacks.
2.2 What the Package Includes
Your package should include the following items. If anything is missing or
damaged, contact Black Box Technical Support at 724-746-5500.
• Network Termination Unit (NTU-1)
• U interface cable
Customer Premise
Equipment
Central Office
Terminal
Adapter
NT2
NTU-1
2-wire
2B1Q Code
S Interface
T Interface
U
Interface
ISDN
2B + D
and/or 4-wire
ASI Code
LAN
WAN
PBX
Fax
PCs