Notes On Non-Doubler Gnlb Loopback Test Procedures; A1Lb, A2Lb, And A5Lb Test Procedures - ADC HiGain HLU-200 List 2D User Manual

150-200-124-02, Issue 2
4 Have the CO tester send the HLU-200 List 2D (4 in 7) in-band loop-up for five seconds. Observe that a
"NLOC" HLU-200 List 2D loopback is in effect. The loopback state is indicated by the GREEN LOOP LED
on the front panel and is also displayed in the Span Status screen.
5 Repeat Step 2. If the test passes, the problem is in the downstream direction. If it fails, the problem is in the
upstream direction.
N N
OTES ON ON
•
The HLU-200 List 2D can be looped-up from the remote location (CREM) by issuing the (6 in 7) command
at the HRU DS1 input port.
• The HRU can be looped-up from the remote location (CLOC) by issuing the (5 in 7) command at the HRU
DS1 input port.
A1LB, A2LB,
AND
To perform the HLU A1LB, A2LB, and the A5LB test procedures:
1 Send into the HLU-200 List 2D the in-band ARMING and NI LPBK code 11000 for at least five seconds.
2 Monitor the output of the HLU-200 for the return of the pattern. Return of pattern indicates that:
• either the HRU has looped-up (if the SMARTJACK LOOPBACK option is ENABLED)
• or that an external NI has looped up (if the SMARTJACK LOOPBACK option is DISABLED) and that
the HLU-200 List 2D and HRU units have been ARMED.
3 Verify, if possible, that the HRU LOOPBACK LED is flashing, indicating that the HRU is armed or lights
steadily, indicating that it is both armed and in loopback.
4 Once armed the HLU-200 can be looped back (see NLOC in
configurations) by sending Intelligent Office Repeater (IOR) LPBK activation code 1101 0011 1101 0011
(D3D3) for at least five seconds. The tester observes the following activation response in the order presented:
a Two seconds of all ones pattern
b Five seconds of returning data pattern
c 231 logic errors (including the frame bit) occurring in the returned pattern comprising:
• 10 errors if ILR-1 (Doubler 1) was sent
•
200 errors if ILR-20 (Doubler 2) was sent
•
20 errors if ILR-2 (HRU) was sent
•
normal looped data
This error pattern will repeat every 20 seconds as long as the IOR loopback pattern is being sent. This also applies
to ILR, Time-Out Override and Query commands.
Some Intelligent Repeater (IR) test sets do not count frame errors as bit errors when the test
pattern is framed and the HLU-200 is set to the AUTO framing mode. To improve compatibility
with those test sets, the HLU-200 generates 201 (NDU2) and 232 (NLOC) ID bit errors. As a result,
the HLU-200 may indicate one more or one less bit error, depending on the test set type and the
number of frame bits contained in the block of errored bits. To avoid this uncertainty, ADC
recommends sending the IR commands unframed.
HLU-200 List 2D
- GNLB L
DOUBLER
A5LB T
EST
February 10, 1999
T
OOPBACK EST
P
ROCEDURES
Figure 24 on page 27
GNLB Loopback Test Procedures
P :
ROCEDURES
for non-doubler loopback
31