Importance

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Abstract

The above described problems are solved and a technical advance achieved in the field by the data stream independent printer of the present invention. This printer is a nonimpact printer that is compatible with host processors that are programmed to operate line printers and host processors that are programmed to operate nonimpact printers. This compatibility is achieved by the use of conversion apparatus that emulates the operation of a line printer, such as a high speed band printer, when the associated host processor is programmed to operate high speed line printers. The conversion apparatus responds to the line printer control signals produced by the host processor to control the operation of the nonimpact printer. This conversion apparatus stores a plurality of character set definitions, overlays, copy modifications and setups on a disk drive memory located in the printer system so that the band definition information provided by the host can be translated into print character generation control signals. In operation, the host processor transmits a band identification data to the printer system, which data is used to retrieve from the disk memory to form and format of the character set that is available to the host processor. The host processor then transmits lines of printing into a line buffer located in the conversion apparatus. The lines of printing are formatted by the host processor as data indicative of a selected character on the print band and its desired position in the line of output print. The conversion apparatus translates the character identification and position into control signals that cause the nonimpact printer to generate the requested character in the requested position on a page basis with any named overlays and copy modifications. The use of this conversion apparatus enables nonimpact printers to be substituted for high speed line printers without any corresponding reprogramming of the software on the front processor. The conversion apparatus emulates the operation of a high speed line printer to the host processor while simultaneously emulating a nonimpact printer programmed host processor to the nonimpact printer.

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First Claim