Abstract: A repeater allows terminals of a first communications system, employing a first air protocol or radio interface, to communicate with terminals of a second communications system, employing a second air protocol or radio interface different from the first. Where the first and second air protocols differ only in operating frequency, but are otherwise compatible, the repeater may linearly translate signals from the first operating frequency to the second operating frequency, and vice versa, without demodulating and remodulating the signals. Where the air protocols differ in other ways, the repeater receives and demodulates signals from the first system, converts the signals to a common format, and remodulates and retransmits the signals according to the second air protocol (and vice versa), in the same frequency bands or in different frequency bands.

Abstract: A process for preparing a textile fiber of sulfonated poly(p-phenylene terephthalamide) that is rapidly dyeable to deep shades.

Abstract: A system and method for handing back a movable transceiver to a different cell site from the original cell site includes circuitry for sensing signals from the movable transceiver which are transmitted on a modified frequency as well as circuitry for translating those signals back to their originally assigned frequencies without changing the detected field strength of the signal, in combination with circuitry for forwarding the translated signals to the different cell site for hand-off evaluation. The method includes sensing the received signals, translating the received signals to an originally assigned frequency based on either a fixed offset or other provided information concerning the translation along with a step of continually updating those frequencies which are to be retranslated.

Abstract: A system for coupling a plurality of telephones or local units to a remote land line telephone system includes a line interface associated with each of the telephones or local units. Each of the line interfaces is in turn coupled to an audio switch matrix. Outputs and inputs to and from the audio switch matrix are coupled to a 4 to 2 wire hybrid, a tone interface hybrid and a computer based control unit. The control unit includes a programmed microcomputer with interface circuits enabling it to communicate with and to control the line interfaces and the audio switch matrix. The computer also includes interface circuits enabling it to communicate with and control a radio transceiver. The radio transceiver is in radio frequency communication with a corresponding radio transceiver remotely located and coupled to the remote land line telephone system. Communications with the remote land line telephone system can be initiated by any of the local units.

Abstract: Arrangement for establishing communication between a first mobile radio station and a second mobile radio station through a repeater over a radio frequency channel selected from a plurality of such channels. In an idle mode, a mobile station searches the channels for a predetermined group signal identifying it as belonging to a particular group of mobile stations. When that predetermined group signal is received on a channel, the mobile station is enabled on that channel so that it can communicate with a call originating mobile station belonging to the same group. In a call originate mode, a mobile station searches for an idle or unused channel identified by the absence of a busy signal. When an idle channel is found, the call originating station transmits a busy signal. The repeater, hearing the busy signal, transmits an acquisition signal.