Mobile system keeps U.N. team in touch

The U.N. team held in a Baghdad parking lot by Iraqi troops keeps in touch with the outside world using a sophisticated device called a "land-transportable" communications system, said Judith DelZoppo of theCommunications Satellite Corp.

The units, which cost between $36,000 and $45,000 depending on the manufacturer, include a telephone, fax machine, portable computer, radio modulator, small satellite dish and battery pack, she said.

Widely used by television organizations during the Persian Gulf war, land transportables pack into two suitcase-sized carrying cases and can be used from almost any point on Earth. The technology was developed for the U.S. military for global communications. It became available commercially several years ago.

To use the telephone or any of the unit's other devices, the caller sets up its small dish antenna on a tripod and points it in the general direction of one of several commercial communications satellites. Then the caller refines the aim using a meter that measures the strength of a special signal broadcast by that satellite.

Once the signal is locked on, the caller then dials a sequence of numbers into the phone that beams a carrier signal to the satellite. A transponder aboard the satellite relays the signal to a large dish antenna called an Earth station -- COMSAT's station in Southbury, Conn., for example.

From there, the unit is connected to the domestic telephone network.