For an introduction to ArtPoll and ArtPollReply, please refer to Discovery Packets.
The ID field is 8 bytes in length and contains the null terminated string of ASCII characters:
A r t – N e t
The purpose of the field is to identify the packet as an Art-Net protocol packet. All Art-Net packets start with this field. Receivers must check this field is correct and discard the packet if it is not.
The OpCode field is a 16-bit word transmitted low byte first. The OpCode identifies the packet type. In the ArtPoll packet this field is set to ‘OpPoll’.
The ProtVer field is a 16-bit word transmitted high byte first. It identifies the version of the Art-Net protocol. The protocol version is not related to Art-Net 1, II, 3 or 4. Only one protocol version has ever existed in production equipment which is 1410. Receivers should use the following good packet test:
ProtVer >= 14
The ProtVer may be increased in a future releases to identify significant functionality changes.
The Flags field is a single byte encoded as bit fields. The bit fields all control basic protocol behaviour of the node that receives the packet. The following table defines the fields.
The Priority field is one byte in length and specifies the minimum priority of diagnostics message that the controller wishes to receive. This field can be ignored if diagnostics messages are disabled in Flags->2.