HUNTER provides a range of communications error messages to warn the user of failure situations. The error messages are designed to be trapped by the Basic ON COMMS statement and handled by the user's program.
However, the errors can occur when HUNTER is under manual control (for instance, in TERM mode) or if the user's application does not contain ON COMMS. In this event, HUNTER will display:
* * * Communication Failure * * * -- Error nn --
where nn is the Error number. The attempt at communication can be aborted either by powering the HUNTER off or by pressing ENTER, in which case control is passed back to the DEMOS file manager.
The available error messages are:
This is due to not receiving any reply in a request for the line, usually caused by incorrect connection of the comnunications channel. (Synchronous mode only).
After establishing the line, a buffer has been sent to which no response has been given, despite 10 ENQs having been sent. (Synchronous mode only).
The wrong positive acknowledgement has been given to a buffer, despite confirmation requests. (Synchronous mode only).
Repeated transmission of a buffer gets only the NAK response, has tried 10 times. (Synchronous mode only).
No ENQ has been received in reply to a WACK (synchronous mode only).
No data has been received to a request for input (e.g. LINPUT) for the specified time.
Transmission has not been able to take place for the specified time.
The error number is available in the location COMERR (see Memory Locations).
No response has been received for 30 seconds.
Three attempts have failed to get an ACK.
Ten re-transmissions have failed to get an ACK.