Verilink APS 2000 T1 Line Protection (880-502411-001) Product Manual - Manual (Page 75)

Diagnostics
Verilink APS 2000 User Manual 5-11
After making the initial speed and channel assignment, you can
switch back and forth between full T1 testing and DSO testing by
using the CSU Configuration menu, option A. Choice 1 = Full T1
testing; Choice 2 = DSO testing at n x 56kbs; and Choice 3 = DSO
testing at n x 64kbs. The originally selected channels remain in
effect until changed and need not be re-selected when switching
between modes.
Commanding the
Remote DSO
Loopback
Use the Craft interface Diagnostic (DIAG) menu to command
loopbacks and send/receive test patterns. The menu also provides
a graphic which shows the received signal condition in real time.
The U and D menu selections initiate the sending of inband loop-up
or inband loop-down codes. Since both T1 loop codes and V.54
loop codes are inband signals, which type is sent depends upon the
drop and insert mode selected in the CSU Configuration menu. If
Choice 1 (Full T1) were selected in the CSU Configuration menu,
then asserting Inband Up (U) in the Diagnostics Menu would cause
the sending of T1 loop-up inband code. If Choice 2 or 3 were
selected in the CSU Configuration menu, then V.54 loop-up code
would be sent, in only the selected DSO channels when Inband Up
is asserted in the Diagnostics Menu. The same applies to Inband
Down (D). Note that while in the Diagnostics Menu, the currently
selected drop and insert mode is indicated following the Inband Up
and Inband Down message.
Sending Test
Patterns and
Detecting Errors
In the Diagnostics Menu, Choices 1, 2, 3, and 4 provide for sending
one of four different test patterns to the far end, (in place of the
normal traffic signal), and for monitoring the received signal for
the same pattern. Any errors detected are indicted both in the
graphic and in an error counter. This function may be applied to
either the full T1 signal or to the selected DSO channels in the same
manner as loopback commands discussed above. If you make no
selection for a test pattern, then the normal data flowing through
the CSU in the selected DSO continues toward the far end. Note that
sending DSO test patterns in the selected channels is independent
of channel loopbacks and may be accomplished whether or not a
DSO loopback has been commanded.
Special
Considerations
when Using V54LB
The V.54 loopback commands may be sent at any time on any line,
whether a system is switched to the spare or is operating on its
normal working line. However, if the DTE of interest is switched to
the spare, then the V.54 loopback and test commands must be
initiated from the spare switch/CSU. This is because the working
line is no longer in the end-to-end circuit. If V.54 loopback or test
signals are initiated on the vacated working line, they will arrive at
the far end switch/CSU, but go no further.