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Loopback Operation 152-402-145-02, Issue 2
30 June 16, 2000 H2TU-R-402
A3LB and A4LB Test Procedures
The H2TU-C can be looped back by sending the Addressable Office Repeater (AOR) LPBK activation code
1111-1111-0001-1110 (FF1E) for at least 5 seconds. This causes the H2TU-R-402 to enter the NLOC state. The
H2TU-C Loopback Time-out (LBTO) setting determines the duration of this loopback unless it is overridden by
the reception of a second identical 16-bit loopup command before the timer expires. When this time-out override
state exists, the only way to loop the H2TU-R-402 down is to issue one of the three loopdown commands listed
in Table 12. The automatic time-out mode is restored during subsequent loopback sessions.
Table 12 summarizes the codes required to execute Addressable 3 (A3LB) and Addressable 4 (A4LB) repeater
loopback commands. All code sequences must be present for at least 5 seconds.
Table 12. Addressable Repeater Loopback Commands (A3LB and A4LB)
Name Description Binary Code
(a)
(Hexadecimal Equivalent)
(a) The leftmost bit arrives first in all sequences. The detection algorithm functions reliably with a random 10
-3
Bit Error Ratio (BER)
on the facility. The entire arming and loopback sequence can also be initiated at the remote H2TU-R location.
NLOC H2TU-R-402 loopup from NI 1111-1111-0001-1110 (FF1E)
CREM H2TU-R-402 loopup from CI 0011-1111-0001-1110 (3F1E)
NREM H2TU-R loopup from NI 1111-1111-0000-0010 (FF02)
CLOC H2TU-R loopup from CI 0011-1111-0000-0010 (3F02)
SMJK H2TU-R loopup from NI 11000-11000-11000 ...
SMJK H2TU-R loopup from NI
(b)
(b) Not supported by A4LB.
100000 100000 100000 ...
SMJK H2TU-R loopup from NI (ESF-DL) 1111-1111-0100-1000 (FF48)
Loopdown H2TU-C and H2TU-R loopdown from NI OR CI 11100-11100-11100 ...
Loopdown H2TU-C and H2TU-R loopdown from NI OR CI 100-100-100 ...
Loopdown H2TU-C and H2TU-R loopdown from NI OR CI (ESF-DL) 1111-1111-0010-0100 (FF24)