User`s guide

B: BSC 2780/3780 Control Procedures

DC 900-1340I 221

B.1.8 Unrecoverable Errors In Transmission

When an unrecoverable transmission error occurs, the BSC 2780/3780 software dis-

cards all messages in the transmit queue. A data acknowledgment containing the appro-

priate error code in the

dlRead pOptArgs.iICPStatus field is returned for each discarded

message. Figure B–10 and Figure B–11 show examples of unrecoverable error handling.

Figure B–10: No Response from the Remote Station

Client Freeway

Remote Station

ACK0

ENQ

EOT

Block 1 (ETB)

Normal data

dlWrite

Data Acknowledge

Block 2 (ETB)

Retry limit exceeded

ACK1

ENQ

No response

ENQ

(DLI_PROT_SEND_NORM_DATA)

dlRead