ADC HiGain H2TU-C-319 List 4E User Manual page 70

Testing
To perform the A2LB test procedures:
1 Send the in-band 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.
If the Arming code is not returned after 5 seconds, the system may be armed, but there is no
active loopback.
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:
a 2 seconds of AIS (all ones pattern)
b 2 seconds of returning data pattern
c Logic errors (including the frame bit) occurring in the returned pattern comprising:
–
231 errors, if IOR LPBK (H2TU-C) 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.
Some Intelligent Repeater (IR) test sets do not count frame errors as bit errors when the test
pattern is framed and the H2TU-C is set to the Auto framing mode. To improve compatibility with
those test sets, the H2TU-C generates 231 (NLOC and CREM) ID bit errors. As a result, the
H2TU-C 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 unframed IR 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
(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 in-band code 11100 or the ESF DL code (FF24).
62
57). If the Time-Out Override code 1101-0101-1101-0110
January 9, 2002
LTPH-UM-1049-02, Issue 2
H2TU-C-319 List 4E