How do trained only skills work with level based skill checks?

[Ozreth]

So if you're using level based skill checks from unearthed arcana how would trained only skill checks like like disable device work?

[Righteous Doggy]

Exactly like any other check, if its a class skill you pretend you have ranks in it, if not, well, that fighter probably isn't going to be able to defuse the bomb quiet as well as the rogue... They wouldn't have any ranks in it, so can't do it. or at least not nearly as well as someone with an idea of how it works.

[Ozreth]

So don't let the fighter try to disable it or just don't let him add his level?

[Righteous Doggy]

He couldn't do it becuase its not a class skill, unless he dipped rogue or took the Skill Knowledge feat. A rogue could do it just fine, since its a class skill.