5.2 POWER-UP / SYNCHRONIZATION
Apply AC power to the Model 1180/35 by plugging the separate AC power adapter first into the rear panel outlet of the Model 1180/35 and then into an acceptable AC power outlet. There is no power switch on the Model 1180/35: When the "power" LED is glowing steady, the Model 1180/35 is powered up. Note: be sure the front panel toggle switch on both Model 1180/35s is set to NORMAL.
After both the local and remote 1180/35s are powered up, a synchronization process must occur between the two modems before a link can be established. Depending upon a number of factors, this synchronization process can take as long as 60 seconds. Any time one of the Model 1180/35s loses power (in a lightning storm, for example), the local and remote units must
When both Model 1180/35s are powered up and passing data normally, the following LED conditions will exist:
•PWR = green
•TD & RD = flashing red and green
•RTS & DCD = green
•TEST = off
5.3LOOPBACK TEST MODES
The Model 1180/35 offers two loopback test modes to evaluate the condition of the modems and the communication link. These tests are activated from the front panel.
5.3.1 LOCAL LOOPBACK
The local loopback test checks the operation of the local Model 1180/35, and is performed separately on each unit. Any data sent to the local Model 1180/35 in this test mode will be echoed back to the user device. For example, characters typed on the keyboard of a terminal will appear on the terminal screen.
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To perform a local loopback test, follow these steps:
A.Activate local loopback by moving the front panel toggle switch DOWN to "Local". Once local loopback is activated, the Model 1180/35 transmit output is connected to its own receiver. The "test" LED should glow. (Note: Even though the local Model 1180/35 cannot communicate with the remote Model 1180/35 in this mode, the synchronized connection between the two modems remains intact).
B.Verify that the data terminal equipment is operating properly and can be used for a test. If a fault is indicated, call a technician or replace the unit.
C.Perform a BERT (bit error rate) test on each unit. If the BERT test equipment indicates no faults and the data terminal indicates a fault, follow the manufacturer's checkout procedures for the data terminal. Also check the V.35 interface cable between the terminal and the Model 1180/35.
5.3.2 REMOTE LOOPBACK
The remote loopback test checks the performance of the local and remote Model 1180/35s, and the communication link between them (see figure 7, on the following page). Any characters sent to the remote 1180/35 in this test mode will be returned back to the originating device. For example, characters typed on the keyboard of the local terminal will appear on the local terminal screen after having been passed to the remote Model 1180/35 and looped back. To perform a remote loopback test, follow these steps:
A.Activate remote loopback by moving the front panel toggle switch UP to "Remote". The "test" LED should glow.
B.Perform a BERT (bit error rate) test on the system.
C.If the BERT test equipment indicates a fault, and the local loopback test was successful for both Model 1180/35s, there may be a problem with the fiber communication line connecting the modems. You should test the fiber line for proper connections and continuity.
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