User`s guide

220 DC 900-1340I
BSC Programmer’s Guide
B.1.7 Recoverable Errors In Transmission
Figure B–9 shows how the BSC 2780/3780 software handles recoverable line errors.
Figure B–9: Recoverable Error Sequence
Client Freeway
Remote Station
ACK0
ENQ
EOT
Block 1 (ETB)
NAK
Normal data
Data Acknowledge
Block 1 (ETB)
Block 2 (ETB)
ACK1
ACK0
Block 3 (ETX)
ENQ
ACK0
Block 3 (ETX)
ACK1
(BCC error)
NAK
(BCC error)
Block 2 (ETB)
(Missed ETX)
.
.
.
Timeout
dlRead
(
DLI_PROT_RESP_LOCAL_ACK)
dlWrite
(
DLI_PROT_SEND_NORM_DATA_EOM)