A communication system includes a plurality of separate transmission units. A common signal line connects the units. A token is transferred from a first of the units to a second of the units during one sequence. The token is a right to output data to the common signal line. When the token is rejected by the second unit, the token is retransferred from the first unit at maximum a predetermined number of times during that sequence to the second unit. When the retransferred token is rejected by the...

A communication aid for a handicapped patient having only eye movement. The aid comprises a rigid transparent panel having a central opening therein and a plurality of transparent overlays each having a central aperture are individually mounted flatwise on the panel with the aperture in the overlay aligned with the opening. Each overlay contains a plurality of illustrations depicting objects or needs of the patient and the illustrations are spaced around the central aperture. An observer looking...

A selective call communication system for use by an untrained person is provided. The communication system includes a number of telephones located in different locations, connected to a central switching unit. A number of selective call radios, each having an address, are assigned to the central switching unit. Upon the use of the telephone, the central unit identifies the telephone in use, and initiates an alerting call to the corresponding selective call radio automatically. The selective call...

A spread communication system comprising a receiver, a diffusion convertor for converting a signal from the receiver, a control signal generator for generating a control signal representing an output level of the diffusion convertor, another diffusion converter for converting data to be transmitted, a transmitter for transmitting data from the another diffusion convertor and a transmission controller for controlling a transmission level of the transmitter in accordance with the control signal fr...

This invention relates to communication systems and more particularly to a communication system wherein a plurality of separate information transmitters can simultaneously transmit information through a common, relatively small bandwidth communication channel to a single commonly-and-continuously shared receiver.

A wall communications outlet having a backplate with a central circular opening; first and second sets of sidewalls ringed about the central opening to act as a storage area for optical fibers or copper wires; and a set of upstanding posts mounted to the backplate with slots therein to accommodate connector panels held in the slots. A variety of connector sleeves can be fitted in a connector panel. Cables can enter the wall outlet through the hole in the backplate or from openings in the side of...

A communication interface for connection to a communication apparatus provided with a balanced-type interface circuit includes a circuit for outputting a constant voltage approximately at the middle of the voltage level of transmitted data signals and is adapted to transmit to a balanced-type receiver contained in the communication apparatus a data signal as one input and the constant voltage from the constant-voltage circuit as another input.

Communication networks, specifically network topologies and apparatus therefor suitable for data communication between computers, tend to be of three main types--those with a star topology (the older sort), those with a bus topology, and those with a ring topology. The ring topology networks have many advantages, but their simpler forms are highly vulnerable to link or repeater failure. The invention proposes another ring network system, which is particularly resilient to repeater and/or link fa...

A communication apparatus such as a facsimile machine switches an auto-receive mode and a manual receive mode by a time and an off-hook detection during a ringing period.

A communication subsystem includes a plurality of peripheral interface devices, one or more network interface devices and, optionally, one or more gateway interface devices. Each and every interface device includes a uniform data transport controller that autonomously controls data traffic across the device associated therewith and executes all requisite communication protocol conversions.