Section 150-619-100
Revision 01
Page 26
15. HLU-619 A5LB TEST PROCEDURES
1. Send the in-band Arming and NI (Network
Interface) 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 “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 bits)
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” and “Arm” (the HLU-619
is still armed) in addition to the margin displays. The
Loopback Time-out option 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
(Network Interface) LPDN and Disarm code 11100.
The automatic time-out timer is restored during
subsequent loopback sessions.
4. When you are done, send the IOR LPDN code
1001 0011 1001 0011 (9393) to loop down the
HLU-619. The unit remains armed as indicated
by the “Arm” message on the HLU-619 and the
flashing of the HRU-612 Loopback LED.
5. Using the following codes, a network tester can
activate loopbacks NLOC or NREM or SMJK (if
ENAbled) (see Figure 5). A customer tester can
activate loopbacks CLOC or CREM.
