Section 150-619-100
Revision 01
Page 25
14. HLU-619 A4LB TEST PROCEDURES
1. The HiGain-2 Line Unit can be looped back
(NLOC in Figure 5) by sending the Addressable
Office Repeater (AOR) LPBK activation code
1111 1111 0001 1110 (FF1E) for at least five
seconds. The HLU-619 enters the NLOC state
(see Figure 5). The display on the HLU-619
alternates between NLOC (network local loop)
and the margin displays. The Loopback Time-
out option (which is user settable to “None,” 20,
60, or 120 minutes) determines 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-619 down is to issue one of the
three loop-down commands listed in Step 2. The
automatic time-out mode is restored during
subsequent loopback sessions.
2. The following list summarizes the codes required
to execute all the HiGain-2 system loopbacks
(see Figure 5). All code sequences must be
present for at least five seconds.
3. All of the above loopbacks can also be initiated
from the front panel of the HLU-619 using the
Mode and SEL buttons ,see paragraph 8.01.
ABBREVIATIONS USED BELOW
LU
Loop Up
LD
Loop Down
NI
Network Interface
CI
Customer Interface
ESF-DL
Extended Super Frame Data
Link
ADDRESSABLE 4 (A4LB) REPEATER LOOPBACK COMMANDS
P
OSITION
N
AME
C
ODE
HLU-619 LU from NI
NLOC
1111 1111 0001 1110 (FF1E)
HLU-619 LU from CI
CREM
0011 1111 0001 1110 (3F1E)
HRU-612 LU from NI
NREM
1111 1111 0000 0010 (FF02)
HRU-612 LU from CI
CLOC
0011 1111 0000 0010 (3F02)
HRU-612 LU from NI
SMJK
11000 11000 11000 ...
HRU-612 LU from NI (ESF-DL)
SMJK
1111 1111 0100 1000 (FF48)
HLU and HRU LD from NI or CI
Loop Down
11100 11100 11100 ...
HLU and HRU LD from NI or CI
Loop Down
100 100 100 ...
HLU and HRU LD from NI or CI
(ESF-DL)
Loop Down
1111 1111 0010 0100 (FF24)
Note: 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.
