Send ENQ every 0.5 seconds waiting for SYN for normally 6
minutes (in case of a retry process, 10 seconds). If CAN
is received or no answer is received, the sending side
aborts data transmission. If any other data is received,
the sending side moves to a retry process.
Wait for ENQ for normally 6 minutes
(in case of a retry process, 10 seconds). If no ENQ is
received, the receiving side aborts data transmission.
SYN must be sent within 0.3 seconds after receiving
ENQ. If the receiving side wants to abort data
transmission, it should send CAn instead of SYN.
If no Data packet is received within 0.4 seconds after
sending SYNs the receiving side moves to a retry
Sending side must start sending Data packet within 0.2
seconds after receiving SYN.
ACK must be sent within 0.4 seconds after receiving the
last byte of the Data packet.
If ACK is not received within 1 second or other
data (including NACK) is received, the sending
side moves to a retry process.
The sending side must finish sending one Data packet
within 4 seconds.
If the last byte of the Data packet is not received
within 5 seconds after receiving the first byte of the
packet, the receiving side moves to a retry
process. If a communication error is detected, the
receiving side must skip all received data until:
- no more data is received for 0.4 seconds or
- 5 seconds pass after receiving the first byte of
the packet, and then moves to a retry process.
In case of a checksum error, send NACK within 0.4
seconds and move to a retry process ...
Sending and Receiving side
If a communication error occurs, both sides try to
transfer the same block again (retry process). The
sending side backs to the stage of sending ENQ, the
receiving side backs to the stage of receiving ENQ. In
this case, the time-out (6 minutes) is reduced to 10
seconds. Retry process must be performed within 1
second after the communication error is
confirmed. Retry process can be done up to 2 times (3
times in total).