ACC X.25 Protocol User's Guide

X.25 Status and Completion Messages
Buffer Completion Statuses
Appendix A132
Buffer Completion Statuses
At the link level (X.25 link ZLU), the following two buffer (write)
completion error statuses may be returned, as well as the more usual
standard statuses. Although these are a part of the standard status set,
they are not used by most protocols, and have a particular significance
within X.25. Either condition will prevent the transmission of any
frames across the local X.25 link. The defines for these status codes can
be found in the zcomstatus.h and zx25status.h include files.
22 IO_LNK_DSC Link disconnected
23 IO_LNK_RST Link reset
For Virtual Circuit ZLUs (Level 3), the following buffer (write)
completion error statuses may be returned.
1 IO_DSBL Terminal disabled
3 IO_BUSY Terminal is busy for too long
20 IO_DOWN Terminal down
21 IO_NO_CALL No call established
Also, the following completion statuses may apply to a configuration
control write to an X.25 link ZLU. These control writes are normally only
issued by the X.25 driver (zx25d).
24 IO_BAD_CTL Bad control function or format
25 IO_INC_CTL Inconsistent control write.
The parameters of the control
write are inconsistent with the
current setup of the logical
channel terminal.
26 IO_UNA_CTL Temporarily unable to process
control write. The logical
channel terminal is not
currently in a proper state for
processing the particular
control function.