First it was Jericho's, then Berlin's; now it's office walls that are tumblin' down. The latest instrument of white-collar freedom is the radio-packet modem. Installed inside a laptop or notebook computer, the device sends and receives data over the airways rather than, as before, over telephone lines. Executives will no longer be forced to devise phone connections from their hotel rooms; similarly, warehouse workers won't have to stay wired to in-house systems, and salespeople will have the ability to set up smart terminals anywhere in the field.

The radio-data modem is basically a transmitter/receiver that operates over a shared public-radio-data network, a special range of frequencies that have been allocated by the Federal Communications Commission for commercial use such as in wireless telecommunication. A step well beyond lo-cal infrared connectivity (see "Networking Without Wires," No. 08910952, August 1991), the new modem, which emulates a Hayes, can connect with other modem-equipped computers almost anywhere in the country.

Although portable computers with integrated radio modems are relatively expensive at this point, your telephone savings can chip away at the cost, since radio-modem connections are not distance sensitive. While a person summoned by a pocket pager in Boston may have to make a $10 toll call to Los Angeles, a person with a radio modem can exchange the same information for about a dime. Even if the modem at the other end isn't turned on, the data can be stored for later delivery by the public radio service that processes the signal. Radio-modem technology should not be confused with cellular-phone connectivity. Radio is not dependent on location and doesn't suffer static or dead spots.

The technology is evolving quickly. Tiny modems manufactured by Motorola (800-759-8877; for technical questions, call 708-576-6641), the major radio player, have already been adapted for the Psion HC hand-held computer (retail approximately $1,000; call 617-237-8538) and the IBM PC Radio (retail $5,500; call 800-426-2468). NCR, Poquet, and Telxon are also planning to introduce portables with integrated radio modems. And Ericsson GE (201-265-6600) is marketing an external version. One problem: airlines may not allow radio-modem use in flight. -- Robert A. Mamis

* * *