Digital Equipment Corporation

Larry Narhi

John Kirk

Thomas Pitman

A signal transmission and receiving system includes a controller or central processor unit and one or more peripheral units interconnected by a transmission line or bus having a plurality of conductors. Instead of providing terminator devices for the opposite ends of the bus in the controller and in the last peripheral unit connected to the bus, respectively, both terminator devices are located in the controller and the bus is looped back on itself so that both ends of the bus can be connected to a connector having two sets of contacts, one set being connected electrically to the conductors at one end of the bus and the other set of contacts being connected electrically to the conductos at the other end of the bus. That connector is arranged to be coupled to a mating connector on the controller, that mating connector also having two sets of contacts, one set being connected electrically to one terminator device in the controller and the other set being connected electrically to a second terminator device in the controller so that when the two connectors are coupled together, both ends of the bus have the proper terminating impedances. Additional connectors spaced along the bus are arranged to be coupled to the peripheral units.

Signal transmission and receiving system with looped transmission line

A bus data path control scheme facilitates communications in a data processing system between subsystem elements that have different data widths. A plurality of buses is provided whereby each subsystem or element is connected to one of the plurality of buses. A control logic array detects requests to transfer data between subsystems. Each of the plurality of buses are connected to one another through a bidirectional transceiver. Once the control logic array detects the request for transferring data between subsystems, the array and the transceiver operate in concert to permit subsystem devices having different data widths to communicate with one another. In particular, the array and transceiver act to redirect data so that as it is shifted from a first bus to which the sending subsystem is connected to a second bus to which the receiving subsystem is connected, the data is moved into the proper bit location on the second bus so as to be received properly by the receiving subsystem.

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Bolton, MA, United States of America

Larry Narhi