ATTN: Ben and Jeff
"I do not mean to actually make an a'dam." Elayne held herself erect, chin tilted in that cool way of hers. She sounded offended, and icily calm. "But it is a ter'angreal, and I have puzzled out how it works. I saw you attend at least one lecture on linking. The a'dam links the two women; that is why the sul'dam must be a woman who can channel too." She frowned slightly. "It is a strange link though. Different. Instead of two or more sharing, with one guiding, it is one taking full control, really. I think that is the reason a damane cannot do anything the sul'dam doesn't want her to. I don't really believe there is any need for the leash. The collar and bracelet would work as well without it, and in just the same ways."
Taken from The Fires of Heaven. Robert Jordan. 1993.