[RQ5.4] Any CRC signature calculation shall start with a preset value of “1”.

[RQ5.5] Any CRC signature calculation resulting in a “0” value, shall use the value “1” instead.

[RQ5.6] SPDUs with all values (incl. CRC signature) being zero shall be ignored by the receiver (SafetyConsumer and SafetyProvider). For Client/Server communication, this means that a Method Call with all fields making up the RequestSPDU being zero shall be answered with all fields making up the ResponseSPDU being zero. Neither of these SPDUs shall be presented to the respective state machines.