Meanings of the Status Codes

The ZCOM status codes are divided into three groups, depending on the associated request code. Within each group, not all status codes apply to all request codes. The groups are:

     Terminal input, output control, and unsolicited errors 
           Request codes: 1, 2, 3 and 5 
 
     Terminal configuration and state control 
           Request codes: 6, 7, 8, 9, 10 
 
     Port configuration 
           Request code: 11 

It it only possible to report one status per status code. When a reporting module detects multiple status conditions, it reports the most important status only.

When a protocol module reports a status condition that it interprets as an error, it is assumed that the messaging operation has been retried if appropriate, and it is not possible to recover from the error condition.

The request codes associated with each error are given as a guide only. A particular status may be reported for another request code within the group, however the status code would have a different meaning in a different group.

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.