Section 150-619-100
Revision 01
Page 20
TESTING PROCEDURES
10. HLU-619 GNLB TEST PROCEDURE
1. Send the HRU-612 (3 in 7) in-band loop-up code
for five seconds. The HLU-619 displays “NREM”
indicating an HRU-612 loopback is in effect (see
Figure 5).
2. Transmit a DSX-1 test signal into the HLU-619
and verify that the returned (looped) signal is
error free.
If the above test fails, transmit the (3 in 5) in-
band loop-down code. Verify that the HLU-619
display returns to normal.
3. Send the HLU-619 (4 in 7) in-band loop-up code
for five seconds. The HLU-619 displays “NLOC”
indicating that an HLU-619 loopback is in effect.
4. Repeat Step 2. If the test passes, the problem is
in the cable pair or the HRU-612. If it fails, the
problem is in the CO equipment.
The NREM, NLOC, CREM and CLOC loopbacks
can also be initiated from the front panel of the
HLU-619 with the Mode and SEL push buttons
(see Section B Paragraph 10.09).
The HLU-619 can be looped up from the remote
location (CREM) by issuing the (6 in 7)
command at the HRU-612 DS1 input port.
The HRU-612 can be looped up from the remote
location (CLOC) by issuing the (5 in 7) command
at the HRU-612 DS1 input port.
11. HLU-619 A1LB TEST PROCEDURE
1. Send the in-band Arming and NI LPBK code
11000 into the HLU-619 for at least five seconds
or at least four repetitions of the 16-bit ESF data
link Arming code 1111 1111 0100 1000 (FF48).
(Left bit arrives first.)
2. Monitor the output of the HLU-619 for the return
of the pattern. Return of pattern indicates that
either the HRU-612 has looped up (if the Smart-
Jack Loopback option is ENAbled) or an external
NI has looped up (if the Smart-Jack Loopback
option is DISabled), and that the HLU-619 and
HRU-612 units have been Armed. Verify that the
HLU-619 display intermittently indicates “Arm”
and also “SMJK,” if the HRU-612 is in loopback.
Also verify, if possible, that the Loopback LED of
the HRU-612 is flashing indicating that the HRU-
612 is armed, or, that the Loopback LED lights
steadily indicating that the HRU-612 is both
armed and in loopback.
3. Once armed the HLU-619 can be looped back
(NLOC in Figure 5) by sending the Intelligent
Office Repeater Loopback (IOR LPBK) activation
code 1101 0011 1101 0011 (D3D3) for at least
five seconds. you see the following activation
response:
♦
Two seconds of AIS (all ones), followed by:
♦
Five seconds of returning data pattern,
followed by:
♦
231 logic errors (including the frame bit)
occur in the returned pattern (20 errors if
ILR-2 was sent), followed by:
♦
Normal looped data.
Note:
This error pattern repeats every 20
seconds, as long as the IOR loopback
pattern is being sent. This same 20-second
repeat scenario also applies to the Time-out
Override and Query commands. It also
applies (with the appropriate number of bit
errors) to the other ILR commands.
The HiGain-2 Line Unit is now in Logic Loopback
(NLOC of Figure 5). The display on the HLU-619
periodically shows “NLOC” (network local loop) and
“Arm” (the HLU-619 is still armed) in addition to 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 Time-out Override
command or a loop-down command is sent. If the
Time-out Override code 1101 0101 1101 0110
(D5D6) is received, the “activation sequence,”
described in step 3 above is repeated, and the
automatic timed expiration of the loopback is
inhibited. If this Time-out Override is sent, then the
only way to loop the HLU-619 down is to issue the
Intelligent Repeater Loop-down (IR LPDN) code
1001 0011 1001 0011 (9393) or to issue the NI
LPDN and Disarm code 11100. The automatic
time-out timer is restored during subsequent
loopback sessions.
4. Upon completion, the tester sends the IOR LPDN
code 1001 0011 1001 0011 (9393) to loop down
