Filter
Top Products
LTPH-UM-1031-03, Issue 3 Testing
H4TU-C-319 List 1 September 12, 2003 53
A5LB Test Procedure
Using the codes listed in Table 18, a network tester can activate NLOC or NREM loopbacks (or SMJK, if
enabled). A tester at the customer premises can activate CLOC or CREM loopbacks.
Table 18. A5LB Addressable Repeater Loopback Commands
Name Binary Code
(a)
(Hexadecimal Equivalent)
(a) The leftmost bit arrives first in all sequences. The detection algorithm functions reliably with a random 10
-3
BER on the facility.
The entire arming and loopback sequence can also be initiated at the remote H4TU-R location.
Description
ARMING or NI LPBK (inband) 11000-11000 ... Arming code
ARMING or NI LPBK (ESF Data Link) 1111-1111-0100-1000 (FF48) Arming code
IR LPDN or DISARM (inband) 11100-11100 ... Disarming code
IR LPDN or DISARM (ESF Data Link) 1111-1111-0010-0100 (FF24) Disarming code
IOR LPBK (NLOC or CREM)
230-232 bit errors
229-231 bit errors
(b)
(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.
1101-0011-1101-0011 (D3D3) H4TU-C loopup
ILR-1 LPBK
(NDU1 and CDU1 10 bit errors)
1100-0111-0100-0001 (C741) Doubler-1 loopup
ILR-20 LPBK
(NDU2 and CDU2 200 bit errors)
1100-0111-0101-0100 (C754) Doubler-2 loopup
ILR-2 LPBK
(NREM and CLOC 20 bit errors)
1100-0111-0100-0010 (C742) H4TU-R loopup
ILR-2 LPBK (NREM or CLOC)
20 bit errors
(c)
(c) The H4TU-R is assigned the ILR-2 loopback code. It responds with 20 bit errors (excluding the frame bits).
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.
1100-0111-0100-0010 (C742)
IR LPDN 1001-0011-1001-0011 (9393) Loopdown (H4TU-C or H4TU-R)
IR QUERY LPBK 1101-0101-1101-0101 (D5D5) Query loopback
IR ALTERNATE QUERY LPBK 1101-0101-1110-1010 (D5EA) Alternate query loopback
TIME-OUT OVERRIDE 1101-0101-1101-0110 (D5D6) Loopback time-out override
IOR POWER DOWN (H4TU-C)
(d)
(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.
0110-0111-0110-0111 (6767) Removes HDSL4 line power