@jamesdhatch The “arc OK” signal is provided on the Hypertherm CPC port and wired with the Hypertherm supplied interface cables. It’s the correct way to handle pierce delays. I don’t believe there is anything legally stopping Langmuir from using the signal, in fact they are encouraged to use it. Other systems such as CANDCNC provide support for it. And finally here is a post from Langmuir way back in May where they say support is planned:
Note the post 2 above that one where @jimcolt recommends using the 12/14 contacts for arc ok.