First came the 900 megahertz phones for better security and sound quality. Then 2.4 gigahertz, and now 5.8GHz. Just how many “hertz” do we need? It turns out that as baby monitors, pagers, and cell phones crowd out the lower ranges, 5.8GHz is best for maximum security and least interference. Only a handful of these phones are available now, but count on more coming soon.

AT&T 5840
PROS: Usual phone features, plus extras such as an answering machine with three mailboxes,vibration "ring" option, and four sound settings. CONS: No speed dialing: no direct dial from the base unit.
BOTTOM LINE: A snazzy-looking phone with a complete set of accessories and extras to round out a solid system.

UNIDEN TRU5885-2, $229
PROS: Only model that always uses a 5.8GHz connection (others switch between 2.4 and 5.8). Comes with two handsets that double as speakerphones.

CONS: The base unit accepts two handsets, max.

BOTTOM LINE: Great set of features and price, but look elsewhere for handsets to scatter around your home or office.

VTECH VT5831, $180
PROS: Sleek phone can work with up to six handsets, which offer Caller ID and clock displays.
CONS: First to market can mean a few bugs in design and reception.
BOTTOM LINE: Try it, you might like it — but before you rely on it at your company, give it a test run in your home office first.