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CHAPTER 5: Operation
5.4 V.54 Test Modes
The Async/Sync Industrial Line Driver offers two V.54 test modes to evaluate the
condition of the modems and the communication link. These tests can be
activated physically from the front panel or via the RS-232 interface.
NOTE
V.54 test modes are available for point-to-point applications only.
5.4.1 L
OCAL
A
NALOG
L
OOPBACK
(LAL)
The Local Analog Loopback (LAL) test checks the operation of the local
Async/Sync Industrial Line Driver and is performed separately on each unit. In
this test mode, any data sent to the local Line Driver will be echoed back
(returned) to the user device. For example, characters typed on the keyboard of a
terminal will appear on the terminal screen.
To perform a LAL test:
1. Activate LAL. You can do this in one of two ways: by moving the front-panel
toggle switch to Local or by raising pin 18 on the RS-232 interface (Make sure
DIP-switch S2-6 is OFF, and DIP-switch S3-5 is ON). Once LAL is activated, the
Line Driver’s transmit output is connected to its own receiver. The Test LED
should be lit.
2. Verify that the data terminal equipment is operating properly and can be used
for a test. If a fault is indicated, call Technical Support.
3. Perform a BER (bit error rate) or 511/511E test on each Line Driver. If the
BER-test equipment indicates no faults, but the data terminal indicates a fault,
follow the manufacturer’s checkout procedures for the data terminal. Also,
check the RS-232 interface cable between the terminal and the Line Driver.