HDLC-Frame Protocol User's Guide (February 2004)

Using HDLC.FRAME Protocol
Status and Error Messages
Chapter 324
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 3-2 Z7340A Interface Unsolicited Status Codes
Unsolicited
Status Code
Description
IO_OK No error detected.
Normal communications have been established
or resumed.
IO_DSBL Terminal Disabled
ST25XDCD Loss of DCD signal
ST25XCTS Loss of CTS signal
IO_STATS This message is sent in response to a
CW_STATS control write. The data buffer
contains a x25l2stat_type structure (defined in
zcomx25.h)