Compliance, Section note, Ds3 niu3 12-slot housing – ADTRAN NIU3 User Manual

Page 2: Alarms, Options, Turnup, Operation, Led indication, Maintenance, Signal relays

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DS3 NIU3 12-Slot Housing

Alarms

A 3-post, wire-wrap terminal (

) on the housing backplane selects either a normally closed (

COM/NC

) or a

normally open (

COM/NO

) alarm relay. The alarm relay output responds to the card malfunction status on

individual NIU3 modules. To connect the alarm relay:

1. Determine if the desired alarm output is an NO or NC response.
2. Make wire-wrap connections accordingly.
3. If not already done, connect alarm output to designated terminations.
4. After wiring connections are made, replace security covers.
5. Following installation, ensure stability of the assembly has not been upset.

OPTIONS

Aside from connecting redundant power and alarm NO/NC selection, there are no options associated with the
housing.

TURNUP

When an NIU3 module is inserted into a housing with power applied, the

STATUS

LED illuminates red while the

NIU3 performs a self-test. If the test passes, the

STATUS

LED illuminates green, indicating the NIU3 is online, and

the other LEDs go through an on/off sequence. If the test fails, the LED remains red, and the bypass relays
(ADTRAN patent pending) on the shelf maintain data flow around the NIU3.

OPERATION

The NIU3 12-Slot Housing exchanges data to and from the network loop and customer loop via the back panel
BNC connectors. During operation, the NIU3 is transparent to data flow. If the NIU3 fails or is removed from the
circuit, the relays on the housing backplane provide pass through transmission so data flow is maintained.
In the event of circuit trouble, test equipment at the central office can monitor the loop. When a loopback is
initiated, the transmit/receive paths can be tested to the customer interface. NIU3 troubleshooting tests are intrusive
to data transmission.

LED Indication

There are no LEDs on the NIU3 12-Slot Housing. LEDs on the individual NIU3 modules provide configuration
and status information.

COMPLIANCE

NEBS

Level 3

ANSI

T1.404

60950

NOTE: Use one of the following requirements for powering the unit locally:

1. Connect to a grounded –48 VDC source, electrically isolated from the AC source. Provide branch

circuit overcurrent protection with a fuse or circuit breaker, minimum 48 VDC, maximum 3 amps.
Provide an approved and rated easily accessed disconnect device in the field wiring.

2. Connect to an approved Class 2 Type (LPS) power supply rated at 48 VDC, maximum 240 VA.

For those slots not populated with an NIU3 module, blank covers (P/N 1212076L1) must be installed.

MAINTENANCE

Except for signal and alarm relay replacement, the NIU3 12-Slot Housing does not require maintenance for normal
operation.

Signal Relays

Each loop has a cut-through signal relay accessible on the backplane. The relay ensures data transfer in the event the
NIU3 module fails, is removed, or loses power. Failure of the relay is determined by process of elimination. If a loss
of signal occurs and all other parameters are satisfactory, then a failed relay is indicated. A Relay Replacement Kit
(P/N 1212072L1) is available from ADTRAN.
Follow this procedure to replace a failed signal relay:

1. Insert a jumper strap on the posts immediately beneath the suspect relay to provide a signal path relay bypass.

CAUTION:

Observe prong configuration on the removed relay. Relays are polarity sensitive and replacement
relays must be oriented correctly.

2. Using an appropriately-sized IC extractor tool, remove the relay.
3. Align and insert the replacement relay in the correct orientation, taking care not to bend prongs.
4. Remove the jumper strap.
5. Monitor for normal operation.

Alarm Relay

The alarm relay is located adjacent to the alarm wire-wrap pins on the backplane. The alarm relay output responds
to the card malfunction status on individual NIU3 modules. If an alarm condition occurs but an alarm signal is not
present, then a failed alarm relay is indicated. Follow this procedure to replace a failed alarm relay:

1. Using an appropriately-sized IC extractor tool, remove the relay.

CAUTION:

Observe prong configuration on the removed relay. Relays are polarity sensitive and replacement
relays must be oriented correctly.

2. Align and insert the replacement relay in the correct orientation, taking care not to bend prongs.

CIRCUIT DIAGRAM

COM