Using HDLC/LAP-D Protocol
Status and Error Messages
64 | ST25ENBL† | Link NOT established on ENABLE |
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| This status message is generated in response to a |
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| terminal enable request after it is determined that |
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| multiple frame acknowledged operation can not be |
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| established. The down bit will always be set. |
65 | ST25DSBL | Link disconnected on DISABLE |
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| This status message is generated in response to a |
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| terminal disable request after multiple frame |
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| acknowledged operation has terminated. The down bit |
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| will always be set. |
77 | ST25ENF | ENABLE failed - bad config |
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| This status message is generated in response to a |
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| terminal enable request when the terminal’s |
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| configuration is invalid. The down bit will always be |
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| set. |
The following status messages are sent after an error occurs when the link is in multiple frame acknowledged operation. The error conditions include cable faults, inability to receive acknowledgment of transmitted frames or receiving frames that are inconsistent with multiple frame acknowledged operation. When one of these error conditions occur, the protocol attempts to reestablish multiple frame acknowledged operation. After the attempt has either succeeded or failed, the unsolicited status message that reflects the original error condition is sent. If the attempt fails, the link is considered disconnected and the down bit will be set in the status; otherwise the link has only been reset and the down bit will be clear.
66 | ST25XDCD | Link disc. on loss of carrier |
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| The card is no longer receiving the required |
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| communications signals. This can be caused by incorrect |
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| port configuration or disconnected/faulty cabling. |
68 | ST25RTRY† | Exceeded retransmit limit |
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| A frame was transmitted N200 times without receiving |
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| an acknowledgment from the remote. |
34 | Chapter 3 |
