There are a lot of inconsistencies in the explanations of how the a'dam is supposed to function. The experiment with Siuan and Leane - and later Setalle Anan - makes it clear the sul'dam needs at least to be able to channel, but if she ever actually did so the glow would be visible. So if the sul'dam require the ability to channel but never actually use it, what are they doing with it?

I once argued that the a'dam was less a linking device than a compulsion device. Perhaps if you're going to give control of one woman's channeling to another, that other needs to have the same physical/mental channeling structures available to them in order to use the ability. But the sul'dam only develop them to the point where they can engage with the damane's channeling and no further. It would explain why Aviendha judged the sul'dam she and Rand met to be right on the edge of being able.

But to answer your question, a shielded sul'dam would be like Siuan and Leane - able to sense the damane but not effect her, including directing her channeling. It's unknown whether the damane can walk around or channel in this state or whether it's the same for her as if the bracelet is on a peg on the wall.