Wireless messaging is relatively new, making its debut in 1992 with EMBARC (Electronic Mail Broadcast to A Roaming Computer), built by Motorola as a nationwide one-way message service aimed at mobile executives and field-office workers who required access to e-mail. EMBARC is based on the 931-MHz paging technology Motorola acquired when it purchased Contemporary Communications, Inc. in 1990. Today, EMBARC provides coverage spanning 250 cities in the United States and Canada.

Users can send messages from any e-mail system that has an EMBARC interface. Typically, the user accesses EMBARC on a PC and addresses a message to one or more recipients. The message is then sent through an X.400 gateway to a central switch, which stores and translates it for satellite transmission. The message travels from the satellite to one or more regional transmission sites that rebroadcasts it at 931 MHz to a Motorola NewsStream receiver, which interfaces with a mobile computer via the standard RS-232C serial port. The data transmission rate is 300 bps. High priority messages may be repeated to assure quality of reception.

Upon message notification, the user uploads the message to a PC running EMBARC software. Menu options guide the user through the process of creating, editing, reading, storing and printing messages. The software can be configured to automatically direct messages to the desired application when NewsStream is connected and the computer is turned on.

Users may send the same message to as many recipients as needed at no extra cost, even if they...