When the local and remote Multi-Function LD Cards are both powered up and are passing data normally, the LEDs on the Cards will look like this:
•Power: Steadily lit
•TD and RD: Flashing red and green
•RTS and CD: Green steadily lit, red dark
•Test and Error: Dark
5.4 V.54 and V.52 Diagnostic Tests
The Multi-Function LD Card offers two V.54 test modes and two V.52 test modes to evaluate the condition of the modems and the communication link. Both sets of tests can be activated physically from the front panel. The V.54 test can also be activated from the RS-232 interface.
NOTE
V.54 and V.52 test modes on the Multi-Function LD Card are available for point-to-point applications only.
5.4.1LOCAL ANALOG LOOPBACK (LAL)
The Local Analog Loopback (LAL) test checks the operation of the local Multi-Function LD Card, and is performed separately on each unit. Any data sent to the local Multi-Function LD Card in this test mode will be echoed (returned) back to the user device. For example, characters typed on the keyboard of a terminal will appear on the terminal’s screen. To perform a LAL test, follow these steps:
1.Activate LAL. You can do this in either of two ways. One is to move the upper front-panel toggle switch labeled “Remote—Analog” to the “Analog” (right-hand) position. The other is to raise the signal on Pin 18 of the RS-232 interface (switch S3 position 5 must be “On”—see Section 3.1.4). Once LAL is activated, the Card’s transmit output is connected to its own receiver. The Test LED should light.
2.Verify that the attached DTE is operating properly and can be used for a test.
3.Move the lower front-panel toggle switch labeled “511/E—511” to the “511” (right-hand) position. This will activate the V.52 BERT test mode and inject a 511 test pattern into the local loop. If any errors are present in the loop, the Error LED will blink sporadically.
