Section 150-619-100
Revision 01
Page 13
9.08
HiGain-2 may take longer than normal to
respond to in-band loopback commands when its
framing mode is set to UNFR, and the in-band
commands are sent in either an SF or ESF mode.
The frame bits override the command bits and
cause errors in the command sequence. These
errors cause HiGain-2 to reject some sequences.
This can extend the detection interval.
9.09
Pressing both the Mode and SEL front
panel buttons for at least three seconds, to start a
Manual Loopback session. This session allows the
user to select one of four HiGain-2 loopbacks. The
message, “MAN LPBK,” appears on the front panel
display followed by the message “NLO?” If you
press the SEL button is pressed at this time, an
NLOC loopback is executed changing the message
from “NLO?” to “NLOC.” If the Mode button is
pressed instead of the SEL button, “NLO?” is
replaced by “NRE?” This now allows an NREM
loopback to be executed with the SEL button.
Pressing the Mode button two more times yields the
“CRE?” (CREM) and “CLO?” (CLOC) customer
loop-back options in the sequence listed. This
interactive button procedure permits any of the four
HiGain-2 loopbacks to be executed. The next
loopback option can be presented by pressing the
Mode push button, however, the previously
executed loopback will remain active until the SEL
push button is pressed, and a different loopback is
activated. If, after 30 seconds, neither button is
pressed, this manual loopback session terminates,
and the normal margin displays reappear. If this
time-out occurs with an active loopback in effect, the
appropriate loopback and loop margin messages
appear. Once the manual loopback session
terminates, the loopback remains in effect until it
times out in accordance with the user LBTO setting.
It can also be terminated by re-entering the manual
loopback mode and selecting another loopback.
Only one loopback can exist at any given time.
Pressing both the Mode and SEL buttons again for
three seconds, terminates any active loopback, ends
the Manual Loopback session, and returns the
display to normal. Note that these same loopbacks
can be initiated from the RS-232 maintenance port
by choosing the Loopback Mode, option D, from the
Main Menu. This displays the Loopback Menu (see
Figure 9), from which any of the loopbacks can be
initiated/terminated.
