Spaced-apart communication controllers connected to a cable-based network place a portable device in communication with the network for transfer of data packets. Each controller communicates with the portable device with packet transmissions through air, and requires registration of the portable device before offering packet transferring services. The registration process involves transmitting a packet from the portable unit requesting a response from controllers, transmitting a response packet from each controller receiving the request, selecting one of the responding controllers at the portable unit according to criteria that enhance data transfer, and transmitting from the portable unit a packet identifying the selected controller to complete registration. The selected controller transmits to other controllers via the network cable a packet confirming the registration. A controller with which the portable device was previously registered responds by de-registering the device and transmitting any stored packets addressed to the device via the cable to the newly selected controller. A power saving protocol is implemented for a battery-operated portable device and adjusted continually to accommodate the rate at which transmissions to the device occur. The power saving arrangement includes disabling the receiving section of the device.