Abstract: A simple and flexible over-air protocol for use with a mobile telephone system, having hand-held telephones in a micro cell or other type of cellular communication system. A method in which user stations communicate with one or more base stations to place and receive telephone calls, in which the user stations are provided a secure voice or data link and have the ability to handoff calls between base stations while such calls are in progress. Each base station has a set of "air channels" to which it transmits in sequence. The air channels supported by each base station are called that base station's "polling loop". A user station receives general polling information on an unoccupied air channel, transmits responsive information to the base station, and awaits acknowledgment from the base station. Each base station may therefore simultaneously maintain communication with as many user stations as there are air channels in its polling loop.

Abstract: A personal communications system is described which includes components of software and hardware operating in conjunction with a personal computer. The user interface control software operates on a personal computer, preferably within the Microsoft Windows.RTM. environment. The software control system communicates with hardware components linked to the software through the personal computer serial communications port. The hardware components include telephone communication equipment, digital signal processors, and hardware to enable voice, fax and data communication with a remote site connected through a standard telephone line. The functions of the hardware components are controlled by control software operating within the hardware component and from the software components operating within the personal computer.

Abstract: A supervisory image communication system by an ISDN includes a parent station and a plurality of child stations connected to the parent station by way of an ISDN basic interface and an ISDN switched network. Any of the child stations transmits call originating information to originate a call to the parent station, and the parent station supervises, in response to the call originating information, the state of the child station in accordance with image information subsequently inputted thereto from the child station. When a child station detects an emergency condition and tries to notify this to the parent station, a call originating reason representative of information of the emergency condition is added as sub-address information to call originating information to be transmitted. Upon acceptance of such call originating information from the child station, the parent station detects the sub-address information thus transmitted thereto and identifies the call originating reason.

Abstract: N bit-collision circuits of a collision detection circuit each include a bit-collision circuit driver connected to drive an x-th line of the common collision detection bus if the x-th line of the station's corresponding identifier signal is at a low level. The bits of the identifier signal are only provided to the bit-collision circuit drivers while an enable signal is asserted. The driver has an open-collector-type connection to the x-th line of the common collision detection bus. That is, the bit-collision circuit driver, when not driving, presents a high impedance at its output. Each bit-collision circuit further includes an XOR device for use in comparing the level of the x-th line of the collision bus with the level of the x-th bit of the station's identifier signal. A NOR device is for combining receives the comparison results from the XOR devices of the bit-collision circuits and provides a combined bit-collision result.

Abstract: A method of providing loop free and shortest path routing of data packets in a network having a plurality of switches, routing messages for communicating network topology information between the switches, a plurality of links connecting the switches and a plurality of channels connecting the switches to the links. The loop free routing of data packets is achieved through modifications to known link state packet (LSP) routing protocols and permits each switch to inform adjacent switches in the network of the information in the switch's database used to compute forwarding tables. A switch uses a received LSP to compute a forwarding table and informs neighboring switches on attached links of the routing change. The switch discards any subsequent data packets whose path would be affected by the changed routing information.

Abstract: A congestion control scheme for connectionless networks relieves congestion by routing a portion of traffic on a congested primary path onto a predefined alternate path constructed such that loop-freedom is guaranteed. Explicit care is taken to avoid spreading congestion onto alternate paths. The control actions are taken in a completely distributed manner, based on local measurements only and therefore no signaling messages need to be exchanged between nodes.If desired, lower loss priority may be assigned to alternate routed traffic. Congestion is monitored locally and thresholds defined to declare the onset and abatement of congestion. The present invention affords at least an order of magnitude improvement in end-to-end cell blocking under sustained focussed overload.