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5.0 OPERATION
Once the Model 2090 is installed and configured properly it is
ready to place into operation. This section describes the function of
the LED indicators, the use of the loopback test modes and the control
port.
5.1 LED DESCRIPTIONS
The Model 2090 Series is equipped with seven LED indicators that
monitor the status of communication. Figure 3 (below) shows the loca-
tion of the LEDs on the Model 2090 Series front panel.
TXD
(Transmit Data) glows green to indicate data flow to
Model 2090 from the DTE.
RXD
(Receive Data) glows green to indicate data flow from the
Model 2090 to DTE.
LOS
(Loss of Sync) glows red to indicate a network Loss of
Frame or Loss of Signal condition.
RXD
LOS
ALM
ERR
T/L
PWR
TXD
Model 2090
Figure 3. Top of Model 2090, Showing LED Indicators
Model 2090
ALM
(Alarm) glows red to indicate that one of several alarm
conditions exist. These conditions may be local alarms
or remote alarm conditions. Alarms may occur due to:
• Loss of Synchronization
• Loss of Frame
• AIS (Blue Alarm)
• Yellow Alarm
ERR
(Error) flashes to indicate errors. There are several flash-
ing patterns to indicate the type of error.
Invalid Switch Configuration: It is possible to request
more bandwidth than is possible. For instance, if you set
the starting channel to 12, and you select a number of
timeslots exceeding 13, the unit will not be able to satisfy
your request. In that case, the ERR LED will flash once a
second (fi second on, fi second off). When the unit
detects an invalid setting, it will ignore the setting and
default to a full T1 (bandwidth = 24 channels, starting
channel = 1). This will continue until you set the switches
to a valid setting. The invalid switch configuration condi-
tion overrides other error conditions.
• Errored Second: In ESF or SF framing, if
the unit detects a frame error, the ERR LED will flash
briefly once a second.
• Framing Mismatch: the ERR LED flashes briefly once
a second when framing modes are mismatched.
• Loss of Signal: When there is no signal at the network
interface, the ERR LED will flash briefly once a second.
TST
(Test/Loop) glows yellow to indicate that the unit is in a
test mode. The unit may be in any one of the following
modes:
• D4 Line Loop (CO initiated)
• ESF Line Loop (CO Initiated)
• ESF Payload Loop (CO Initiated)
PWR
(Power) glows green to indicate that the unit is receiving
power.
