CHAPTER 4: Operation
45
Table 4-2. Stat mux indications.
No.
Indication
Probable Cause
Action
1
ERR lit
Stat mux problem
Turn the stat mux off, then turn it on again or
press RESET. If ERR indicator remains lit,
replace the stat mux.
2
TEST lit
1. Stat mux in
Check whether the stat mux is being configured,
command mode
and wait until configuration is completed (at any
time, only one sub-channel can be in the
command mode).
2. Stat mux in
Enter command mode. Select the
diagnostics mode
DIAGNOSTICS item to see whether one of the
test loops is on. If a test loop is on but is no
longer needed, disconnect it.
3
MAIN not lit
Problems in com-
Check whether communication equipment
(SYNC may also
munication link to
is powered and properly connected, then use
flash)
remote STM
the diagnostics function described in
Chapter 5
to find the fault.
4
SYNC flashes
1. Remote stat mux
Check whether the remote stat mux is powered
continuously
operational
on, and operates normally.
(MAIN indicator
lights)
2. Problems in com-
Check whether communication equipment is
munication link to the
powered and properly connected, then use the
remote stat mux
diagnostics function described in
Chapter 5
to
find the fault.
5
OVF lights
Stat mux buffers full
One of the DTE units connected to the stat mux
does not respond to flow-control commands.
Check that all the DTEs do have a flow-control
option, and that stat mux flow control is properly
configured.
6
One or more
1. No traffic on
If traffic is expected, but no activity is indicated,
sub-channel
sub-channel
check the DTE equipment and its connections.
indicators are
permanently off
2. Stat mux problem
Press the RESET pushbutton, or turn the
stat mux off, then on again. If the ERR indicator
lights, replace the stat mux.
