Communications Errors

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:

Error 01: Unanswered line bid

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).

Error 02: No response from receiver

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).

Error 03: Response not matched by odd-even block count

The wrong positive acknowledgement has been given to a buffer, despite confirmation requests. (Synchronous mode only).

Error 04: Retransmission rejected

Repeated transmission of a buffer gets only the NAK response, has tried 10 times. (Synchronous mode only).

Error 05: Loss of response from receiver.

No ENQ has been received in reply to a WACK (synchronous mode only).

Error 06: Not used.

Error 07: Not used.

Error 08: Receive timeout Error

No data has been received to a request for input (e.g. LINPUT) for the specified time.

Error 09: Transmit timeout Error

Transmission has not been able to take place for the specified time.

The error number is available in the location COMERR (see Memory Locations).

Error 10: ETX/ACK timeout Error

No response has been received for 30 seconds.

Error 11: ACK/NAK failure

Three attempts have failed to get an ACK.

Error 12: Systime failure

Ten re-transmissions have failed to get an ACK.