Pathport firmware now includes a toggle called ArtNet Alternate Mapping, that resolves the issue described below.  When the Alternate Mapping is selected, a Pathport node will output ArtNet universe 0:0 as Univ 1.  However, for people still using older firmware, or those curious about one of the quirks of ArtNet, we leave the following posted.

Occasionally we get phone calls because ArtNet data isn't being distributed as expected on a Pathport system.  Usually one of two things is going on.

First, ArtNet is a protocol, not a standard.  There is no single version of the protocol that is more 'correct' than all the others.  Even using the latest doesn't guarantee compatibility because the issue is implementation. 

So, although we feel our implementation is pretty thorough, there is no guarantee it will be compatible with someone else's implementation.  ArtNet is quite robust, but it does happen from time to time that two versions of the protocol do not get along.  Recently we determined one manufacturer had done an endian swap (the most significant and least significant bytes were reversed) which affected the packet header and caused communication to fail. 

Typically, when protocol interpretation is causing the problem, errors are widespread within a universe, seemingly random or the system simply doesn't work.  But compared to the other issue, protocol implementation errors are rare.

The other common issue is an off-by-one problem, which is the result of ArtNet using two values to calculate the universe number.  Originally, Artistic Licence devices used two sixteen-step rotary switches to determine the universe.  The rotaries are numbered from 0 (zero) through to F - a base sixteen set up.  Using this arrangement, the lowest possible universe number is 0:0. 

Pathway, and most other manufacturers, use a base ten counting system.  The lowest universe number for Pathport devices is universe one.  We've explored ways of remapping ArtNet universe 0:0, but the most elegant - so far - of many ungainly solutions is for Pathport devices to ignore this ArtNet universe.

The usual result is that ArtNet universe 0:0 is not available.  However, we have encountered some media servers, including the Maxxyz, that present ArtNet 0:0 to the user as being Universe 1.  When the media server is used with the same manufacturer's ArtNet-DMX nodes, everything is fine, as the gear knows about the translation.  But when used with third party nodes, such as ours, everything appears off-by-one.  Universe 1 disappears, universe 2 shows up as universe 1, 3 as 2 and so on.  The only solution is to change the paperwork.

The link on this page is for a simple conversion chart showing the two-part, base-sixteen ArtNet universe and its corresponding Pathport universe number.  "Subnet" is shown as most significant - but be aware that this may not always be the case.