Rockwell International Corporation

Bell + Howell Company

Dev R Rattan

Robert R Parker

Harry J Dyke

Donald E Koch

Jeffrey L Gottesman

Mark A Dempsky

Digital loop carrier system having CPU to channel unit protocol. A method of communicating with the protocol is used in a telecommunication system having at least a central processing unit (CPU) connected to a plurality of digital interface units (DIU) via a communication module (CM). Each of the digital interface units is connected to a plurality of channel units (CU). The method has the steps of: sending from the CPU to the COM a command message having at least a first DIU address of a selected DIU of the plurality of DIU's, a channel address of a selected CU of the plurality of CU's, a second DIU address, the second DIU address being substantially identical to the first DIU address, and a first information portion; sending substantially the command message from the COM to the plurality of DIU's, the selected DIU receiving the command message; and in the selected DIU removing the first DIU address from the command message to form a modified message, and sending the modified message from the selected DIU to the plurality of CU's, the selected CU receiving the modified message. The selected module provides a response message to the CPU. The protocol provides a comprehensive response format which identifies the responding module, type of response, and if in error, who detected the error and type of error detected.

Digital loop carrier system having CPU to channel unit protocol

A channel redundancy system for use with a central office connected to a remote location. A central office terminal at the central office has a plurality of channel units including at least one spare channel unit. A remote terminal at the remote location also has a plurality of channel units including at least one spare channel unit. The channel units in the remote terminal are correspondingly associated with the channel units in the central office termimal. From a repair service bureau located remote from both the central office and the remote location in a defective channel unit can be identified and replaced by the spare channel unit.

Channel redundancy in a digital loop carrier system

An intelligent interface arrangement is provided for controlling operation of peripheral devices including a video device and a random access slide projector from a computer. The computer via the interface arrangement also controls the audio and video inputs to the system monitor for the selection of either audio channel from the video device, no audio, or mixed audio. The video control includes selection of video from the video device or computer. The computer addresses the interface arrangement with a predetermined unique address code. The address also includes the category of video device to be controlled. Each command sequence from the computer to the interface arrangement includes a start of command byte, one or more command bytes and an end of command byte. Each communication command sequence also includes a video-audio device command byte for selection of desired audio and video modes. The video-audio device command byte in a preferred arrangement also includes a bit of information for designating the type of video device within a category. The interface arrangement senses the status of the connected video device and slide projector including video device and slide projector connection status, the type of video device connected, power-on status, and operational mode status. The interface arrangement responds to status request by the computer to supply the status of each peripheral and the internal status of the interface components. The interface arrangement also communicates various error and status messages including acknowledgement of received command sequences and for error in agreement between the requested and connected perpheral device.

Computer controlled video device and slide projector interface

Apparatus is provided for the control of a video tape or cassette recorder by a microcomputer. The apparatus is interfaced to the video recorder for the input and output of various control signals via the remote control connector of the video recorder. The apparatus also includes interconnections to a microcomputer, a monitor and the audio and video signals of the video recorder. The apparatus under the control of the microcomputer controls operation of the video recorder and selectively supplies either video recorder video or microcomputer video to the monitor and independently supplies one of the two audio channels of the video recorder or no audio to the monitor. The apparatus under keyboard inputs from the microcomputer controls transport functions of the video recorder including rewind, fast forward, various play speeds, stop and pause. The apparatus also controls random access and presentation of addressable frame segments and locations of a video tape or cassette and maintains an accurate frame count throughout various transport functions with respect to an accurately defined starting point.

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Chicago, IL, United States of America

Dev R Rattan