Loopback Operation
150-231-165-01, Revision 01
44
September 22, 1998
HLU-231 List 6E
These selections determine the duration of this loopback, unless it is overridden by the reception of a second
identical 16-bit loop-up command before the timer expires. When this time-out override state exists, the only way
to loop the HLU-231 down is to issue one of the three loopdown commands listed in Step 2. The automatic
time-out mode is restored during subsequent loopback sessions.
summarizes the codes required to execute Addressable 3 and 4 (A3LB and A4LB) repeater loopback
commands. All code sequences must be present for at least 5 seconds. The abbreviations used in
are as
follows:
•
LU = LoopUp
•
LD = LoopDown
•
NI = Network Interface
•
CI = Customer Interface
•
ESF-DL = Extended Super Frame Data Link
Information specific to HiGain doublers is shown in bold in
.
Table 15.
Addressable 3 and 4 (A3LB and A4LB) Repeater Loopback Commands
Position
Name
Code
a
a The left-most 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 be initiated at the
remote HRU location.
HLU-231 LU FROM NI
NLOC
1111(F)
b
1111(F)0001(1)1110(E)
b This is the HEX number for the 4-bit group.
HLU-231 LU from CI
CREM
0011(3)1111(F)0001(1)1110(E)
HDU DOUBLER 1 FROM NI
NDU1
1111(F)1111(F)0000(0)1000(4)
HDU DOUBLER 1 FROM CI
CDU1
0011(3)1111(F)0000(0)0100(4)
HDU DOUBLER 2 FROM NI
NDU2
1111(F)1111(F)0000(0)0110(6)
HDU DOUBLER 2 FROM CI
CDU2
0011(3)1111(F)0000(0)0110(6)
HRU LU FROM NI
NREM
1111(F)1111(F)0000(0)0010(2)
HRU LU FROM CI
CLOC
0011(3)1111(F)0000(0)0010(2)
HRU LU FROM NI
SMJK
11000 11000 11000 …
HRU LU FROM NI (ESF-DL)
SMJK
1111(F)1111(F)0100(4)1000(8)
HLU and HRU LD FROM NI OR CI
Loopdown
11100 11100 11100 …
HLU and HRU LD FROM NI OR CI
Loopdown
100 100 100 …
HLU and HRU LD FROM NI OR CI (ESF-DL)
Loopdown
1111(F)1111(F)0010(2)0100(4)