Troubleshooting
If the 7511 Dual DSU does not turn on the OK LED after its
Symptom | Possible Cause | Recommendations |
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No power, or LEDs | H The power supply to the | If other devices in the carrier are |
are not solidly lit. | carrier has failed. | functioning, ensure that the card is |
| H The card is not seated | completely seated in the rear |
| connector plate and that the | |
| properly. | |
| connector plate is tightly fastened to | |
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| the carrier backplane. |
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The DSU has detected an | H Reset the card by pulling it | |
fails. Only the Alarm | internal hardware failure. | slightly out of the carrier then |
LEDs are on after |
| replacing it. |
| H Contact your service | |
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| representative. |
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An Alarm LED is on.
DDS Mode: | H Verify the subscriber loop rate. | |
H The subscriber loop | H If the NS LED is lit: | |
rate is not matched to | ||
± Verify that the DSU is | ||
the 7511's configured | ||
connected to the network | ||
rate. | ||
± Request a CSU loopback from | ||
H No DDS Signal | ||
your network service provider | ||
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LADS mode: | Configure both units to the same | |
H The 7511 configured rate | rate. | |
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does not match its |
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partner's rate. |
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Crossed pair connection. | Check interface connections and | |
(LADS mode only: If the RX | cable. | |
leads are connected to |
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each other, the NS LED |
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also will be on.) |
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One of several other alarm | H If the OOS LED is lit: | |
conditions exists: | ± Check the status of the remote | |
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H Out of Service | DSU | |
± Initiate a Remote Loopback | ||
H Out of Frame | ||
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H Bit errors detected | H Try a different DSU with the | |
during loopback test | same network connection. If the | |
(which also causes an | problem persists, contact your | |
Out of Frame condition) | service representative. | |
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12 | January 1999 |