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LTPH-UM-1031-03, Issue 3
A5LB Test Procedure
Using the codes listed in
enabled). A tester at the customer premises can activate CLOC or CREM loopbacks.
Name
ARMING or NI LPBK (inband)
ARMING or NI LPBK (ESF Data Link)
IR LPDN or DISARM (inband)
IR LPDN or DISARM (ESF Data Link)
IOR LPBK (NLOC or CREM)
230-232 bit errors
(b)
229-231 bit errors
ILR-1 LPBK
(NDU1 and CDU1 10 bit errors)
ILR-20 LPBK
(NDU2 and CDU2 200 bit errors)
ILR-2 LPBK
(NREM and CLOC 20 bit errors)
ILR-2 LPBK (NREM or CLOC)
(c)
20 bit errors
IR LPDN
IR QUERY LPBK
IR ALTERNATE QUERY LPBK
TIME-OUT OVERRIDE
IOR POWER DOWN (H4TU-C)
(a) The leftmost bit arrives first in all sequences. The detection algorithm functions reliably with a random 10
The entire arming and loopback sequence can also be initiated at the remote H4TU-R location.
(b) The H4TU-R identifies CREM (and the H4TU-C identifies NLOC) with 231 bit errors, including the frame bits. When framed
data is being sent in the Auto framing mode, the number of the 231 bit errors detected by the test set varies from 229 to 231,
depending on whether or not the test set counts frame errors as bit errors, and on the number of frame bits contained in the
block of 231 error bits. The H4TU-R and H4TU-C generate this bit pattern in a series of discontinuous bursts containing 20-bit
errors each, including frame bits. Those test sets that do not count frame error bits as data bit errors will indicate fewer bits
than the H4TU-R and H4TU-C transmit for a CI and NI loopback.
(c) The H4TU-R is assigned the ILR-2 loopback code. It responds with 20 bit errors (excluding the frame bits).
(d) The IOR Power Down code must remain present for the duration of the power down mode. When this code is removed, the
system returns to its normal unlooped and unarmed state.
H4TU-C-319 List 1
Table
18, a network tester can activate NLOC or NREM loopbacks (or SMJK, if
Table 18. A5LB Addressable Repeater Loopback Commands
(a)
Binary Code
11000-11000 ...
1111-1111-0100-1000 (FF48)
11100-11100 ...
1111-1111-0010-0100 (FF24)
1101-0011-1101-0011 (D3D3)
1100-0111-0100-0001 (C741)
1100-0111-0101-0100 (C754)
1100-0111-0100-0010 (C742)
NREM—DSX-1 signal is looped back to
the network at the H4TU-R.
CLOC—DS1 signal from customer is
looped back to the customer at the
H4TU-R.
1001-0011-1001-0011 (9393)
1101-0101-1101-0101 (D5D5)
1101-0101-1110-1010 (D5EA)
1101-0101-1101-0110 (D5D6)
(d)
0110-0111-0110-0111 (6767)
September 12, 2003
(Hexadecimal Equivalent)
Description
Arming code
Arming code
Disarming code
Disarming code
H4TU-C loopup
Doubler-1 loopup
Doubler-2 loopup
H4TU-R loopup
1100-0111-0100-0010 (C742)
Loopdown (H4TU-C or H4TU-R)
Query loopback
Alternate query loopback
Loopback time-out override
Removes HDSL4 line power
Testing
-3
BER on the facility.
53
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