ADTRAN DS3 NIU3 PM, Установка и эксплуатация

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26 Issue 5, February 2011 61213075L2-5E
5. TESTING
The NIU3 is compatible with standard test equipment.
Digital testing is accomplished with the T-BERD 310 or
equivalent.
FEAC Loopback
The test device at the CO inserts a DS3 NIU FEAC (Far
End Alarm and Control) loop up code (C-bit parity
framing only) toward the NIU3. The NIU3 then
performs a network loopback. The loopback is termi-
nated by a DS3 NIU FEAC loop down code.
Loopback and Bypass Configurations
There are four basic NIU3 normal/loopback configura-
tions:
I. Normal Operation
II. Network Loopback
III. Customer Loopback
IV. Dual Loopback
Each configuration is shown in a block diagram in
Figure 29 on page 27. Each block diagram represents
the NIU3 circuit card in normal operation or a particular
loopback.
Each block diagram illustrates the relative position of
the detecting circuits to one another and the LED
indication associated with each, plus the location of the
mid-size monitoring jacks. See
Table 2 on page 5 for
LED descriptions.
Bypass Operation
The bypass relays are represented in block diagram I
only. The bypass relays are independent of the NIU3
circuit card and loopback configurations. The relays
switch to the bypass position during one of the
following conditions:
• The NIU3 PM fails or loses power
• The NIU3 PM is removed
• Flash upgrade is in progress
In-band Test Codes
Remote testing can also be conducted using in-band test
codes. The CO test device inserts the arming code:
1011100 for 5 seconds. After 5 seconds the test device
has 20 seconds to transmit one of the following test
identifier codes:
• 1101 0011 1101 0011 D3D3h Loopback
• 0010 1110 0010 0011 2E23h
2^23-1
• 0010 1110 0010 0000 2E20h QRSS
• 1101 0111 0100 0001 D741h Blue
• 1101 0111 0100 0010 D742h Idle
• 1101 0111 0100 0011 D743h User Defined
The first code initiates a Loopback at the customer
interface in the network direction. The remaining codes
send the associated test pattern in both network and
customer directions simultaneously. To deactivate a
loopback or test pattern, send 1110110, and the NIU
will respond immediately.
NIU test patterns are framed according to framing of the
incoming signal at the NIU network interface at the
moment an NIU in-band test pattern is activated. The
User Defined test pattern is set to the last test pattern
programmed on the NIU
Loopbacks and Test
Commands
screen.
Initiating Loopback with LBK SEL Pushbutton
The front panel
LBK SEL
pushbutton controls three
loopback modes as described here:
• To initiate a loopback toward the network , press
LBK SEL
once and hold for 5 seconds. During this
time the
NTWK LBK
LED flashes rapidly indicating
the network loopback is arming. After 5 seconds the
network loopback enables; the
NTWK LBK
LED
illuminates solid; and
LBK SEL
can be released.
• To initiate a loopback toward the customer , press
LBK SEL
twice and then hold for 5 seconds. During
this time the
CUST LBK
LED flashes rapidly
indicating the customer loopback is arming. After 5
seconds the customer loopback enables; the
CUST
LBK
LED turns on solid; and
LBK SEL
can be
released.
• To initiate a dual (bidirectional) loopback, press
LBK SEL
three times and hold for 5 seconds.
During this time the
NTWK LBK
and
CUST LBK
LEDs flash rapidly indicating the dual loopback is
arming. After 5 seconds the dual loopback enables,
the
NTWK LBK
and
CUST LBK
LEDs turn on solid,
and
LBK SEL
can be released.
If
LBK SEL
is released before the arming period expires
the loopback does not initiate. This feature decreases
the chance of an inadvertent loopback.
If a loopback is in effect, pressing
LBK SEL
will disable
the loopback regardless of initiation point.
Loopback priority is in response to the most recent local
or remote input. The
LBK
LEDs show status.
The NIU3 features additional testing available in the
loopback and test commands menus. Manual loopback
and BERT tests are available as shown in the
Loopback
and Test
commands menu screens.