Installation; Figure 2. Niu3 Circuit Diagram - ADTRAN NIU3 Installation And Maintenance Practice

Description
The NIU3 12-Slot Shelf is an all-metal construction
housing that has slots for 12 NIU3 circuit cards. Card
guides direct the card to the backplane edge connector
and when properly inserted, thumbscrews on the NIU3
front panel align and fasten to threaded holes recessed
on the shelf interior. A removable transparent front
panel with locking hasp provides security. The
backplane circuitry is protected by a metal cover that
has openings for BNC data jacks, power terminal
connections, and alarm pins. Removable covers
provide security for power and alarm connections.
Two cable management bars and wire tie-down
anchor points complete the assembly. All connections
are clearly labeled.

2. INSTALLATION

C A U T I O N C A U T I O N !
SUBJECT TO ELECTROSTATIC DAMAGE
OR DECREASE IN RELIABILITY.
HANDLING PRECAUTIONS REQUIRED.
After unpacking the unit inspect it for damage. If
damage is noted, file a claim with the carrier, then
contact ADTRAN. See Warranty and Customer
Service.
Install per requirements of NEC NFPA 70. After
installation, ensure equipment rack stability is not
upset.
Location
The NIU3 12-Slot Shelf installs at any location
convenient to the customer as a demarcation and
loopback point for DS3 circuits.
Portable
Test
Set
DACS
Test
Head
2
Central Office
DSX-3
ADM
XCONN
Panel

Figure 2. NIU3 Circuit Diagram

Section 61212078L2-5, Issue 1
The NIU3 can pass both network and customer signals
up to 900 feet. However, if either distance exceeds
450 feet, the respective front panel monitoring signal
begins to degrade. Also, during NIU3 bypass
operations, if total transmission distance exceeds 900
feet, signal quality may degrade. See Figure 2 for
maximum recommended transmission distances.
The NIU3 shelf mounts in a standard 19-inch or
23-inch bay. Reversible mounting flanges adjust to
desired position in the appropriate bay.
• Determine desired shelf extension from the bay
frame.
• Position the mounting flanges as necessary using
the appropriate flanges for 19-inch or 23-inch
bay. Install using supplied counter-sink screws.
• Install cable management bars to the rear cover
of the shelf using supplied pan-head screws.
• Mount the shelf to the bay accordingly.
Wiring
Wiring consists of three elements: data, power, and
alarms. Use suitably sized copper conductors only.
Data
Externally, the shelf backplane has four BNC
connectors for each of the twelve NIU3 slots: two
upper (IN/OUT) for network receive/transmit, and two
lower (IN/OUT) for customer receive/transmit (see
Figure 3). Cable management bars provide for
tie-wrapping cables.
• Connect the cables to the BNCs on the backplane
for those shelf slots that will be populated.
• If not already accomplished, connect the opposite
ends to their designated terminations.
• Dress and lace the wire runs to the cable
management bars and bay frames as necessary.
Customer Premises
SONET
ADM
Ring
900
DS3
CPE
NIU
Loopback
Button
61212078L2-5A