A theoretical limit of 32,768 universes or Port-Addresses (that is, 32 kiloverses) exist in Art-Net 4. The 15-bit number that is the Port-Address is composed of three separate parts as shown in the following table. The different parts are reported by a node in the ArtPollReply packet.
For a given node, the most significant 11 bits are identical. The least significant 4 bits are defined on a per Input-Port / Output-Port basis. The array variable ‘p’ in the table below is used to describe this and ranges from 0 – 3 for Input-Ports and Output-Ports.
A node designer may opt to implement these address controls in either hardware or software. Whatever the chosen combination, a node which has 4 Input-Ports and 4 Output-Ports would require the following user controls:
- A Net switch in range 016 to 7F16
- A Sub-Net switch in range 016 to F16
- An Universe switch for each implemented input, in range 016 to F16
- An Universe switch for each implemented output, in range 016 to F16
Prior to Art-Net 3, the limit was 256 universes. Art-Net I, Art-Net II, Art-Net 3 and Art-Net 4 devices are interoperable. The 256 universes available prior to Art-Net 3 are simply defined to be the first 256 universes, as shown in the following diagram.