User Manual

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07.93 e1152.doc

CDDL Protocol - Data link level

4.5 Errors management

The transmitting station enters an answer-waiting status after sending a data packet.

A successful transmission (i.e. the receiving station verifies that the CRC is correct) is

signalled to the receiving station by the [DLE, ACK] sequence.

The packet is transmitted again if the [DLE, NAK] sequence or any other characters is

received (even if before the transmission end), as well as if the answer is missing after

the T1 or T2 time.

The Slave station of course cannot transmit the packet again if it has not been again

selected .

The Fig.: 6 and Fig.: 7 show the possible sequences in both the two directions the

data can flow.

Fig.: 6

Fig.: 7