Nitsuko Corporation

Nippon Telegraph and Telephone Corporation

Tie/communications, Inc.

Minoru Shigematsu

Yoshiji Tanimoto

Minoru Okumura

Kinzi Tanaka

Fumikazu Hamatani

Gary Mason

John E Anderson

Joseph W Litterer

A data transmission system between a main CPU and a plurality of sub-CPU's includes a data bus connected between them, a CPU select line for transmitting a CPU select signal from the main CPU to the sub-CPU's, a latch circuit for providing a wait signal to the main CPU upon write or read in the main CPU with respect to the sub-CPU's and a wait clear line connected between the respective CPU's to provide to the latch circuit a wait clear signal upon completion of input and output of the sub-CPU to release the waited state of the main CPU, the transmission system being thereby simplified to reduce installation space and wiring labor.

Data transmission system between a main CPU board having a wait signal

A communications system having a common equipment unit and a plurality of telephone station sets coupled to the common equipment unit comprises a common equipment unit having at least one trunk interface for coupling at least one central office telephone line to the common equipment unit and an analog to digital converter for converting analog signals on the telephone line into digital form, and at least one station interface coupling the common equipment unit to at least one of the station sets by a single wire pair. A plurality of buses couple the trunk interface and the station interface together, the plurality of buses comprising at least one digital voice bus for carrying digitized voice signals, a digital data bus for carrying digital data signals originating from a digital data device and a control data bus for carrying digital data comprising control information for controlling functions in the station sets for routing the data on the digital voice bus and the digital data bus between at least one of the station sets and the telephone line.

Communications system having voice and digital data capability and

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Kawasaki, Japan

Minoru Shigematsu