5
Section 61150279L1-5, Issue 1
61150279L1-5A
jack BRI logic access, 8 kHz and 64 kHz clock
reference, selection of the desired channel unit (1-10),
and the desired test. When the 10 position rotary
switch is used to select a channel unit, the STATUS
LED on the selected unit will Flash red/green for
about 3 seconds then return to the current status. Refer
to U-BR1TE channel unit document, ADTRAN part
number 61150077L1-5, for additional STATUS LED
operation.
Loopback Test (ADR1-ADR6, NT1)
Loopbacks in the network-to-customer direction can
be initiated from either the ISDN switch or the E1
LIU. The downstream direction is automatically
selected based on the card position in the network. To
initiate a loopback, perform the following steps:
1. Insert the TX and RX plugs of the DS0 digital
test set into the bantam jacks on the LIU.
Connect the clock input to the DS0 digital test set
DB-9 connector on the LIU. Configure the test
set for Near Logic and 64 kbps.
2. Select the desired U-BR1TE channel unit using
the DSL switch on the LIU.
3. Select the desired loopback address on the LIU
(ADR1-ADR6, or NT1).
4. Select the desired bearer channel using B1/B2
DIP switch on the E1 BCU.
5. Press the TEST pushbutton to initiate the
loopback test. The DS0 LB status LED will
turn
ON when the loopback is established to the
selected address. If the selected address does not
respond, the DS0 LB LED will remain OFF.
Observe the DS0 digital set for bit errors.
6. To terminate the loopback, press the TEST
pushbutton or remove the transmit bantam plug.
Upon deactivation of the test the DS0 LB LED
will turn OFF.
Loopback tests to additional network addresses can be
performed by changing to another address with the
Loopback Address switch (step 3). It is not necessary
to exit the test mode to select a new address.
If a new U-BR1TE channel unit is selected testing is
terminated. However, pressing the TEST pushbutton
will initiate the previous test arrangement on the new
address. To start from the beginning (ADR1) return to
step 2.
Point-to-Point Test, (CRTX, LPTX)
A point-to-point (straightaway) test can be performed
to either the U-interface (LPTX) or the E1 carrier
interface (CRTX). This test requires craft personnel at
the local and remote channel banks.
To initiate a point-to-point test using a DS0 digital test
set perform the following steps:
1. Insert the TX and RX bantam plugs of the DS0
digital test set into the jacks on the LIU. Connect
the clock input to the DS0 digital test set DB-9
connector on the LIU. Configure the test set for
Near Logic and 64 kbps.
2. Select the desired U-BR1TE channel unit using
the DSL switch on the LIU.
3. Select the desired test direction: LPTX or CRTX
on the LIU.
4. Select the desired bearer channel using B1/B2
DIP switch on the BCU.
5. Press the TEST pushbutton on the BCU to
initiate the test.
6. If the remote unit is a BR1/10 U-BR1TE channel
unit, perform Steps 1 through 4, choosing the
same front panel switch setting. Ensure both test
sets are configured for the same test pattern (511,
2047).
7. Observe the DS0 digital test set for bit errors.
8. To deactivate the loopback, press the TEST
pushbutton or remove the transmit bantam plug.
Upon deactivation of the test the DS0-LB LED
will go Off.
Local Loopback (LPBK)
A bilateral loopback can be initiated for any of the
BR1/10 U-BR1TE channel units for either bearer
channel. A local test pattern source is not required for
this test. To initiate a local loopback, perform the
following:
1. Select the desired U-BR1TE channel unit using
the DSL switch on the LIU.
2. Select LPBK on the Address switch on the LIU.
3. Select the desired bearer channel using B1/B2
DIP switch on the BCU.
4. Press the TEST pushbutton to initiate the test.
The DS0-LB LED will Flash once a second for
B1, or twice in succession for B2.