Abstract: A method and apparatus for transmit power control in a subscriber loop for high frequency data services are described. Transmit signal power levels are maintained at minimum levels for achieving acceptable communications between a transmitter and a receiver. Transmit signal power levels are adjusted dynamically on a link-by-link basis by employing command controllable transmit power attenuators at the transmitters. The transmit power attenuators are controlled by transmit signal power controllers which issue commands to the transmit power attenuators. Excess transmit power is avoided and parasitic signal coupling between communication links is reduced. The advantages are cross-talk reduction, longer loop length and higher data rates.

Abstract: An apparatus and method for maintaining access to lifeline services through telephone sets provided with telephone service from a voice over digital subscriber loop (VoDSL) transceiver during power interruptions are described. All telephone sets associated with the transceiver are connected to a wire loop which supports the VoDSL service in the event of a power interruption to the transceiver. The advantage is the economical provision of lifeline service access to all telephone sets when power is interrupted to the transceiver. Thus, confusion is reduced, safety is enhanced, and access to lifeline services is ensured during emergency situations.

Abstract: A system for notifying users of digital wireless communications that a mobile unit is moving out of range and communication is about to be lost. The system inserts an audible indication as the received signal strength varies. The audible indication can be in the form of noise which is inserted in such a manner that a digital mobile unit mimics the behavior of an analog mobile unit which is moving out of range, in order to provide a readily identifiable indication to the user that the wireless handset is about to go out of range. Such a system can be used to indicate to both users of wireless units, and to telephone users which are in communication with wireless units, that communication is about to be lost.