That's for the wired ones. The wireless ones require a mains supply for the (HC60NG) relay unit.
BTW the CM7xx series looks like a nice lower-cost version of the 9xx series, and I did get one with this in mind, but after looking at its features (or lack of them, compared to the 9xx versions) sent it back. Can't remember specifically what put me off but I reckoned the 9xx were worth the extra.