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Special Character Encoder and Decoder

IP.com Disclosure Number: IPCOM000044549D
Original Publication Date: 1984-Dec-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Gardner, HJ: AUTHOR [+2]

Abstract

In response to a Marker Request control line, a legitimate data pattern ("pseudo marker") is modified by a data encoder so that the "pseudo" marker is translated into an illegal marker character. After the marker generation is completed, the encoder is restored to normal operation so that subsequent data patterns, that happen to contain the "pseudo" marker pattern, are encoded as normal data. The selection of more than one "pseudo" marker will allow for different marker characters, if desired. Marker character detection is integrated with the decoder logic such that minimal modifications to the original decoder are required because the marker detection is a subset of the actual decoder logic.

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Special Character Encoder and Decoder

In response to a Marker Request control line, a legitimate data pattern ("pseudo marker") is modified by a data encoder so that the "pseudo" marker is translated into an illegal marker character. After the marker generation is completed, the encoder is restored to normal operation so that subsequent data patterns, that happen to contain the "pseudo" marker pattern, are encoded as normal data. The selection of more than one "pseudo" marker will allow for different marker characters, if desired. Marker character detection is integrated with the decoder logic such that minimal modifications to the original decoder are required because the marker detection is a subset of the actual decoder logic. The implementation of this type of encode/decode logic for marker generation and detection enables the system to concatenate the marker characters with the normal data, gap, and sync patterns in the data stream. In general, a normal data pattern designated to be a "pseudo" marker is defined to generate the special marker characters not present in normally encoded data. As shown in Fig. 1, when the marker request has been activated or set, the detection of the "pseudo" marker will modify the data encoder combinational logic and thereby generate the required special marker character. The data decoder and marker detect implementation is similar to that of the encoder implementation. It is illustrated in Fig. 2. A flow diagram for normal ope...