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Browse Prior Art Database

Interface for Optional Features in a Point of Sale Sy

IP.com Disclosure Number: IPCOM000052031D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Paska, TM: AUTHOR

Abstract

Interface card 1 is designed to operate on the microprocessor data bus, with specific address locations (FF40=Status/Interrogation, FF50=Condition FF60=Data Input and FF70=Diagnostics) being assigned definite operational functions, which are not normally assigned to memory data storage locations. One card was designed to accommodate the data transfer (parallel by bit) for the OCR-A/B type optical characters, bar codes (both EAN and UPC) and print/punch ticket readers. To accommodate the physical interface differences, two separate cables 2 and 3 are used. A unique pin in each cable is grounded to serve as an identifier to the control program as to the type of device connected, in addition to indicating that the cable is physically and properly attached.

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Interface for Optional Features in a Point of Sale Sy

Interface card 1 is designed to operate on the microprocessor data bus, with specific address locations (FF40=Status/Interrogation, FF50=Condition FF60=Data Input and FF70=Diagnostics) being assigned definite operational functions, which are not normally assigned to memory data storage locations. One card was designed to accommodate the data transfer (parallel by bit) for the OCR-A/B type optical characters, bar codes (both EAN and UPC) and print/punch ticket readers. To accommodate the physical interface differences, two separate cables 2 and 3 are used. A unique pin in each cable is grounded to serve as an identifier to the control program as to the type of device connected, in addition to indicating that the cable is physically and properly attached. The control program then selects the appropriate microcode to interrupt and transfer the input data, or to indicate an error condition based upon the presence or absence of this signal.

The interface card 1 also contains a simple test pattern generator which serves as a verification that the data lines to this card are functional. In addition to this diagnostics circuit, a "Not Read Yet" circuit is employed to confirm that the address lines to card are Functional. These circuits, in combination with the control and diagnostic microcode programs, serve to detect and isolate hardware failures involving this card, and to separate them from the attaching device.

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