152-319-100-02, Revision 02
Troubleshooting
H2TU-C-319 List 1 and List 1C
April 21, 2000
47
To perform the A1LB, A2LB, and A5LB test procedures:
1
Send the inband Arming and NI LPBK code 11000 to the H2TU-C for at least 5 seconds.
2
Monitor the output of the H2TU-C for the return of the pattern. Return of the pattern indicates one of the
following:
•
The H2TU-R has looped up (if the SMJK Loopback option is enabled).
•
An external NID has looped up (if the SMJK Loopback option is disabled), and the H2TU-C and
H2TU-R have been armed.
3
Verify, if possible, that the H2TU-R Loopback LED is either flashing yellow at 4-second intervals (indicating
that the system is armed), or is a steady yellow (indicating that it is both armed and in SMJK loopback). The
H2TU-C Status LED also flashes yellow when the system is armed.
4
Once armed, the H2TU-C can be looped back by sending Intelligent Office Repeater (IOR) LPBK activation
code 1101-0011-1101-0011 (D3D3) for at least 5 seconds. You should observe the following activation
response pattern in the order presented:
a
2 seconds of AIS (all ones pattern)
b
2 seconds of returning data pattern
c
231 logic errors (including the frame bit) occurring in the returned pattern comprising:
–
10 errors, if ILR-1 (Regenerator 1) was sent
–
200 errors, if ILR-20 (Regenerator 2) was sent
–
20 errors, if ILR-2 (H2TU-R) was sent
d
Normal looped data
This error pattern repeats every 20 seconds as long as the IOR loopback pattern is being sent. This also applies
to ILR, Time-out Override, and Query commands.
The H2TU-C is now in logic loopback if the IOR NLOC loopback command was sent. The Time-out
Override command or a Loopdown command can override the selection made for the loopback time-out (see
“Setting the Loopback Time-out Option” on page 43
). If the Time-out Override code 1101-0101-1101-0110
(D5D6) is received after activating a loopback, then the automatic timed expiration of the loopback is
inhibited. If this Time-out Override is sent, then the only way to loop the H2TU-C down is to do one of the
following:
•
Issue the IR (Intelligent Repeater) LPDN (loopdown) code 1001-0011-1001-0011 (9393).
•
Issue the NI LPDN and Disarm inband code 11100 or the ESF-DL code (FF24).
5
Once the test is complete, do one of the following:
•
If the system is to loopdown but remain Armed, send the IR (Intelligent Repeater) LPDN code (universal
loopdown).
If the Arming code is not returned after 5 seconds, the system may be armed but there is no
active loopback.
The Time-out Override function is only valid for the current active loopback. The automatic
time-out timer is restored during subsequent loopback sessions.
