Abstract: A cellular system (FIG. 4) is expanded to allow communication between mobile ground-based units (70 and 72) and mobile air-based units (80 and 78) where the air base units (e.g., a unit in airplane 78) operate above a threshold elevation. Mobile units below the threshold elevation level use local conventional cellular service area and cells whereas mobile units above the threshold are transferred to a frequency reuse pattern having a higher altitude of service and a larger service surface area. Switching between the air cells (41a-41g) and the land cells (26) is performed by determining if two land cell controllers operate at a same frequency both are receiving transmission from the mobile unit. If two land cells of the same frequency receive the same mobile unit transmission, then the mobile unit is above the threshold elevation and assigned to an air cell, else a land cell is used.

Abstract: A radio system user (126) is alerted (129) as to the occurrence of a financial transaction by a customer (118). Data (122) is obtained from the customer (118) and used to identify a radio system user (126), who is authorized to conduct the financial transaction. A message, indicative of the financial transaction, is automatically provided to a radio system and broadcast (129) to the radio system user (126), thereby alerting the user (126) to the financial transaction.

Abstract: A method of allowing use of small, low-power communication systems (20) within the coverage area (11) of larger trunked communication systems. A low-power communication system re-uses the same communication resources used by the larger trunked system whenever sufficient distance exists between large system communication units and the low power system so as to avoid interference. Large system communication units may also be constructed to operate in a dual mode format so as to transmit and receive in a low power mode and on re-used resources, whenever near a low power system or to transmit and receive in a high power mode whenever else necessary.

Abstract: A system is described for providing ISDN services on a PSTN to communication units from an ISDN interface within a resource controller. The communication unit is allowed access to a target such as a subscriber within the PSTN or a communication unit in another cell, in an ISDN environment through entry of a target access number. The ISDN environment may be changed by the communication unit before entry of a target ID number.

Abstract: A method for transparently coupling an encrypted two-way RF communication unit (100) with an encrypted landline communication unit (104). An RF message comprised of a plurality of data frames (401,402, 403) is transmitted from the RF communication unit (100), wherein a plurality of the data frames include encrypted voice information (403). Some bits from the data frames (501,502) are selectively removed, without removing the encrypted voice information (503), to form reduced bit data frames, and the reduced bit data frames are transmitted via the landline to the landline communication unit (104).

Abstract: An intersystem communication path (20, 67) can be established on an as needed basis. Already established paths are fully utilized before new paths are established. Already established paths can be automatically disconnected when no longer needed, or when existing calls can be merged on to fewer lines. Dial up lines can be mixed with dedicated lines. If desired, excess capacity can be guaranteed to accommodate high traffic conditions and/or other conditions that precipitate a likely need for communication services between systems.

Abstract: A network (2) utilizing power conductor distribution and incorporating infra-red (IR) radiation nodes having IR transducers (4, 6, 8). The IR transducers are located in ceiling-mounted lighting fixtures (16, 18, 20) and are connected to power terminals in the lighting fixtures both for powering the IR transducers in operation and for communicating network information. The transducers are thus positioned optimally for good IR communication and require no additional cabling.

Abstract: A subscriber makes its hand-off decision based on time difference measurements between synchronization markers received from adjacent repeaters relative to the synchronization markers received from the subscriber's assigned repeater. The subscriber uses signal quality measurements to identify candidate repeaters with adequate signal level, and the time difference measurements to decide which of these repeaters is geographically closest. Thus, the subscriber unit makes hand-off decisions as its movement closes the distance to an adjacent repeater that can provide an adequate signal level.

Abstract: Shown, herein, is a method of allowing use of small, low-power communication systems within the service coverage area of larger trunked systems. The small, low-power systems are constructed to reuse at least some of the communication resources, also used by the larger system. The large system measures signal strength values of large cell communication units and transfers such values to the small systems. A small system compares the transferred values with a threshold and when the threshold is exceeded, reuses the communication resources under a TDM format within the small system.

Abstract: Shown, herein, is a method of allowing use of small, low-power communication systems within the service coverage area of larger trunked systems. The small, low-power systems are constructed to reuse at least some of the inbound frequencies of communication resources, also used by the larger system. The large system measures signal strength values of large cell communication units and transfers such values to the small systems. A small system also measures the signal strength and compares the measured and transferred values with thresholds and when the thresholds are exceeded, reuses the communication resources under a TDM format within the small system.

Abstract: A way of allowing small, low-power communication units to reuse trunked system communication resources within the service coverage area of the larger trunked system without experiencing significant interference from the trunked system. The low power units (requestors and targets) avoid interference through spread spectrum transmissions.

Abstract: A personal identity authentification system is provided in which parametric data of an authorized possessor is encrypted into a memory of a portable transceiver device. The portable transceiver device, carried by a possessor, may be activated by an identity request transmitted from a nearby, authorized verification device. Upon activation, the portable transceiver transmits the encrypted data to the verification device which, when decoded by a verification unit, provides positive identification of the authorized possessor.

Abstract: Reusing radio frequency specta in a trunked radio system by establishing small cell trunked radio systems within a large cell trunked radio system wherein low power radio transmission occurs permits multiple small cell trunked radio systems in geographically separate locatiosn to use a limited number of radio resources simultaneously, increasing usage of a finite number of communication resources. As used in cellular telephone systems, very low power trunked radio systems separated from each other can reuse the same frequency without interfering with each other or interfering with a large cell trunked radio system license holder.