Currently Millumin support LTC and MTC and implemented a new feature called Network Timecode (NTC)

There is no documentation on NTC and no other devices support this.

Would be great to have a open network based timecode standard like ArtTimeCode, part of Artnet that is already implemented.

A lot of devices are already supporting ArtTimeCode including, GrandMA3, Chamsys, Pangolin Beyond laser software.

https://art-net.org.uk/how-it-works/time-keeping-triggering/arttimecode/