Abstract: A wireless modem includes a radio transceiver and microprocessor-based controlling circuitry. Two or more modems can be individually ported to host computer devices to link them within a computer local area network. Computer data is broadcast in discreet packets which individually contain address information and error detection information that can be processed by the receiving modem. Each modem is programmed to normally operate in a standby receiving condition. Broadcast signals are processed and decoded by the addressed modem prior to being converted to a machine readable format for transfer to a host computer device. The receipt of one packet of data must be verified by the receiving modem before a transmitting modem can broadcast a subsequent packet. Test systems are also provided for monitoring the operational status of a local area network without requiring operational use of host computer devices ported to the modems within the network.