Using HDLC.FRAME Protocol
Status and Error Messages
Unsolicited Status Messages
The unsolicited status messages (mrq.mrqcode = =
ZCOM_MRQCODE_STATUS) are used to inform the application program of events which occur affecting communications with the remote station. The status code “No error detected” is used to inform the application that the remote station is communicating normally. This could occur when an terminal has been enabled, or after an error condition has been cleared.
For status codes within request code 5 (unsolicited status report) bit 7 will be set to indicate the UP/DOWN state of the terminal after the event which caused the status report. Bit 7 will be set if the terminal state was DOWN, and it will be clear if the terminal state was UP. An unsolicited status report of zero (UP, no error detected) is used to indicate the terminal has just come UP after being DOWN.
| Z7340A ACC Interface | |
| The following unsolicited status codes may be received by an application | |
| program from the HDLC.FRAME protocol on a Z7340A ACC interface. | |
Table | Z7340A Interface Unsolicited Status Codes | |
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| Unsolicited | Description |
| Status Code |
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| IO_OK | No error detected. |
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| Normal communications have been established or |
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| resumed. |
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| IO_DSBL | Terminal Disabled |
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| ST25XDCD | Loss of DCD signal |
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| ST25XCTS | Loss of CTS signal |
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| IO_STATS | This message is sent in response to a CW_STATS control |
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| write. The data buffer contains a x25l2stat_type structure |
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| (defined in zcomx25.h) |
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| IO_ALRDY_ENBL | An enable request is received, while HDLC.FRAME is |
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| already enabled. No action is taken and this unsolicited |
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| status code is returned with the UP/DOWN bit set to |
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| reflect the state of the port. |
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28 | Chapter 3 |