Section 150-611-103
Revision 01
Page 20
TABLE 7. HLU-611 TEST PROCEDURES FOR A4LB OPTION
Step
Action
1
The HiGain-2 Line Hit can be looped back (NLOC in Figure 5) by sending the (Addressable Office
Repeater) LPBK activation code 1111(F) 1111(F) 0001(1) 1110(E) for at least 5 seconds. This causes
the HLU to enter its NLOC state shown in Figure 5. The display on the HLU-611 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 loopup command before the timer expires. When this time-
out override state exists, the only way to loop the HLU 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.
2
The following list summarizes the codes required to execute all the HiGain-2 loopbacks shown in
Figure 5. Note that all code sequences must be present for at least 5 seconds.
LU=LOOPUP, LD =LOOPDOWN, NI = NETWORK INTERFACE, CI = CUSTOMER INTERFACE.
Addressable 4 (A4LB) Repeater Loopback Commands
POSITION
NAME
CODE
HLU-611 LU FROM NI
NLOC
1111(F)*1111(F)0001(1)1110(E)
HLU-611 LU FROM CI
CREM
0011(3)1111(F)0001(1)1110(E)
HRU-612 LU FROM NI
NREM
1111(F)1111(F)0000(0)0010(2)
HRU-612 LU FROM CI
CLOC
0011(3)1111(F)0000(0)0010(2)
HRU-612 LU FROM NI
SMJK
11000 11000 11000..
HRU-612 LU FROM NI (ESF-DL)
SMJK
1111(F)1111(F)0100(4)1000(8)
HLU & HRU LD FROM NI OR CI
11100 11100 11100....
HLU & HRU LD FROM NI OR CI
100 100 100 ...
HLU & HRU LD FROM NI OR CI(ESF-DL)
1111(F)1111(F)0010(2)0100(4)
Note: the left most bit arrives first in all sequences. The detection algorithm functions reliably with a
random 10E-3 bit error ratio (BER) on the facility.
3.
The NREM and NLOC loopbacks can also be initiated from the front panel of the HLU with the MODE
and SEL pushbuttons. See Paragraph 7.20 for details.* This is the HEX number for the 4 bit group
