ER | (Flashing Red) - blinks ON/OFF after a 511/511E |
| test has timed out. See Section 5.3.3 (Test Pattern |
| Generator) for more information. |
| • Flashes once to indicate that a CRC error has |
| occurred (during normal operation) or bit errors |
| have occurred (during 511/511E tests). |
| • Only at power up, blinks once every 200 ms if the |
| DTE Rate is set to an unsupported settings |
TM | (Active Yellow) glows yellow to indicate that the |
| Model 1088/K has been placed in Test Mode. The |
| unit can be placed in test mode by the local user or |
| by the remote user. The TM LED will flash for |
| 400 msec when a valid packet is received from the |
| Model 1001MC. |
5.3 TEST MODES
The Model 1088 offers two proprietary loopback test modes, plus a built- in V.52 BER test pattern generator to evaluate the condition of the modems and the communication link. These tests can be activated phys- ically from the front panel.
Overview
Figure 11 below shows the major elements used in the
Framer
Framer
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Figure 11. Block Diagram Model 1088
Framer
The framer is used to determine the status of the line. In normal operation the framer transmits and expects to receive framed packets from the far end. If the framer receives framed packets from the far end, the DSL Link LED will be active. If framed pack- ets are not received, the DSL Link LED will be inactive. The restart procedure uses this information to determine if a valid connection
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