The information contained here are property of DIGITAX Automotive Electronics Italy, and extremely confidential. Any disclosure, copying, distribution to third
party is strictly prohibited.
54
Handshake
The basic handshake is composed by an originator equipment that sends a MESSAGE containing a
complete PACKET, including the command or request.
Usually this packet, being a request shall not contain data in its body.
Since the packet contains the destination address, only the addressed equipment will accept it and
will respond with a MESSAGE with or without data in the PACKET’s body, according to the received
request.
At this point the originator waits (until timeout) for the response that must be ACK (06h) or NAK
(15h).
In case of ACK, the originator sends the next packet, and if NAK resends the same packet up to 3
times.
In case of not receiving the ACK-NAK answer within the defined timeout, the originator re-sends the
same packet up to 3 times, after that the link is interrupted.
At the end of the transmission of the last packet, and after having received the corresponding ACK,
the originator sends EOT (04h) that finishes the link and releases the line.
