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5.0 OPERATION
5.1 LED STATUS MONITORS
The Model 1186RC features six front panel status LEDs that indicate
the condition of the modem and communication link. Figure 10 shows the
front panel location of each LED.
Functions of LEDs are as follows:
Fiber
The green Fiber LED indicates reliable data on the fiber
side
E1
The green E1 LED indicates reliable data on the
G.703/G.704 side
LOS
The red LOS indicates that syncronization between
modems has not been established. Blinking red LOS LED
indicates the
presense of coding errors
NS
The red NS LED indicates that the signal on the fiber side
is too weak to be detected, which can be due to any of the
following reasons:
- break in the fiber optic cable
- length of the fiber optic cable exceeds the maximum dis-
tance
- problem with Fiber LED.
ER
Flashing red ER LED indicates errors in 511 test pattern
TM
The yellow TM LED indicates that modem is in a test mode
(Local/Remote Loopback or 511/511E test pattern). Opaque
TM indicates normal operation.
When the local and remote units have established a link and are passing
reliable data, the following LED conditions will exsit:
· Fiber = GREEN
· E1 = GREEN
· LOS = OFF
· NS = OFF
· ER = OFF
· TM = OFF
5.2 TEST MODES
The following section describes the test patterns and loopbacks
used in the Model 1186RC. The Model 1186RC offers V.54 compliant
local/remote loopback tests, plus a built-in V.52 BER test pattern gen-
erator to evaluate the condition of the modems and the communication
link. These tests can be activated physically from the front panel.
5.2.1 Local Loopback
The local loopback test checks the operation of the local Model
1186RC, and is performed separately on each unit. The following sec-
tion describes how to perform a local loopback test between the
Network and a local connection.
Any data sent to the local Model 1186RC in this test mode will be
echoed (returned) back to the user (see Figure 11). If two Model
1186RC units are linked when the LAL is activated, data sent from the
remote modem will also be looped back to the remote terminal equip-
ment.
Figure 10.
Front Panel of 1186RC
Figure 11.
Local Loopback Diagram
G.703/G.704
Network
To test the local connection, follow these steps:
1. Activate LAL by moving the front panel toggle switch UP to "Local".
Once the Local Loopback is activated, the Model 1186RC transmit out-
put will be connected to its own receiver. The TM LED will light up.
2. Perform a BER (Bit Error Rate) test on each unit using a separate
BER tester. If the BER test equipment indicates no faults, but the data
indicates a fault, follow the manufacturer's checkout procedures for the
data terminal. Also, check the interface cable between the terminal and
the Model 1186RC. The BER test can also be performed using a built-in
511/511E pattern generator. (See section 5.2.3 on how to use the built-in
511/511E pattern generator.)
3. Upon completion of the LAL test, return the front panel switch to the
NORMAL position. The TM LED should turn off.
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Fiber Line
