Computers and the internet are two-way devices.

Christopher Brooke, portrayed by Robert Shafer, is a ten-year old boy genius who has invented a two-way telepathic device.

Still, the research group said it was unlikely that the standalone two-way devices would ever become as big as the one-way pager market was in the late 1990's now that cellphone makers are improving their keypads and two-way capabilities.

This applies to one-way devices only, two-way devices are capable of receiving and viewing switched video.

"If the pet leaves the yard, you'll get a call on your cellphone, P.D.A., or any other two-way wireless device," said Jennifer Durst, chief executive of GPS Tracks in Oyster Bay, N.Y., which has devised a G.P.S.-based system called the Global Pet Finder.

Related Devices Family radios are not the only two-way wireless devices.

Federal Approval Process To speed up the process and eliminate operators, pagers would have to become two-way devices, which is likely to be the end result of a lengthy Federal approval process under way.

I do agree, especially with "two-way devices".