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Section 61250110L1-5, Issue 4
61250110L1-5D
Remote Payload and Line Loopbacks (ESF
Mode Only)
A remote loopback in the ESF mode allows a local
crafts person to further test the T1 line. This provides
testing from one location to limit the need for
additional personnel for troubleshooting.
The HD-10 can request two types of remote loopback
from a Remote T1 Multiplexer: Payload and Line. A
payload loopback results in payload data being looped
back by the remote T1 multiplexer, framing is
regenerated by the remote T1 multiplexer. A line
loopback results in a full loopback by the remote T1
multiplexer, framing is not regenerated by the remote
T1 multiplexer but instead is echoed back to the local
HD-10.
To initiate either a remote payload or remote line
loopback, navigate through the menu as follows:
TEST >> DSX LOOPBACKS >> CURRENT
LOOPBACK
Then select either REMOTE PAYLOAD
LOOPBACK or REMOTE LINE LOOPBACK to
activate the desired test. The HD-10 will return to the
previous screen to show the status of the test. The
LBK LED will Flash to indicate the HD-10 is in test
mode.
To deactivate the loopbacks, navigate through the
menu as follows:
TEST >> DSX LOOPBACKS >> CURRENT
LOOPBACK
To disable either the remote payload or remote line
loopback select NONE. The HD-10 will return to the
previous screen to show the status of the test. The
LBK LED will go Off indicating the test is terminated.
DS0 Testing
The HD-10 supports two types of DS-0 testing:
• loopback
• point-to-point
Each BRI channel will respond to embedded operation
channel (eoc) loopbacks including B1, B2, and 2B+D.
These commands can be initiated from an upstream
device including the ISDN switch, a U-BR1TE, or
ISDN test equipment.
The HD-10 can also activate a loopback in a
downstream device. An onboard 2047 pattern
generator and error checker allow all 10 circuits of the
HD-10 to be tested simultaneously. The loopback test
using the internal pattern generator is controlled via
the faceplate DB-9 interface.
ISDN Loopback and BERT Testing
Network loopback in the customer direction can be
initiated from the DB-9 interface. The 2047 pattern
generator and error checker permit testing of
downstream devices without additional test
equipment. When active the status LED for the circuit
under test will flash. The test status and error logging
are available via the DB-9 interface.
The HD-10 has the following BERT/LOOPBACK
capabilities:
• Tests can be invoked on all 10 of the DSLs in the
HD-10 at the same time.
• Each DSL has the capability to perform B1, B2,
and 2B+D BERT tests.
• Each DSL can perform BERT tests to itself
(ADR1), to 6 units downstream towards the NT1
(ADR2-ADR7), and to the NT1.
The following provides an example of how to initiate
a 2B+D NT1 loopback on DSL 1 via the DB-9
terminal. Navigate through the menu as follows:
TEST >> ISDN LOOPBACKS AND BERT
TESTING >> DSL 1
Perform the following steps to invoke the test:
• Type A to select the 2B+D BERT TEST.
• Type N to select the NT1 address.
• Type S to start the Loopback test.
If the loopback is successful the screen will update the
Test Status to indicate a 2B+D NT1 Loopback is in
progress. The screen will also begin to update the
count for the Total Number of Bits transmitted. Any
errors that occur will be indicated in the Error Bits
section. If the BERT test is dropped downstream for
any reason, the screen will keep track of this in the
Lost Sync section. To reset the BERT counters, type
"0" (zero).
To deactivate the test, navigate through the menu as
follows:
TEST >> ISDN LOOPBACKS AND BERT
TESTING >> DSL 1
Perform the following step to deactivate the test:
• Type “S” again to terminate the test.
