Ax.25 Protocol

Issue : 1 Rev : 1 Date : 19/03/2007 Page : 1 of 11

Phase B/C

Telemetry and Telecommand Transfer Frames Format
Without uplink
Prepared by: Florian George

Checked by: Per Hemso (ESA/ESTEC) Ted Choueiri (EPFL)

Approved by:



ESA/ESTEC Noordwijk Netherland
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19/03/07


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1 RECORD OF REVISIONS
ISS/REV 1/0 1/1 Date 15/03/2007 19/03/2007 Modifications Initial release Update after commentaries by Per Hemso Created/modified by Florian George Florian George

Ref.: S3-BC-SE-1-1b-AX.25 Transfer Frames Format.docx

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2 TABLE OF CONTENTS
1 2 3 RECORD OF REVISIONS ......................................................................................................................... 2 TABLE OF CONTENTS ............................................................................................................................. 3 REFERENCES ............................................................................................................................................. 4 3.1 3.2 4 5 6 APPLICABLE DOCUMENTS REFERENCES DOCUMENTS 4 4

LIST OF ACRONYMS ................................................................................................................................ 5 INTRODUCTION ........................................................................................................................................ 6 TRANSFER FRAMES FORMAT .............................................................................................................. 7 6.1 AX.25 TRANSFER FRAME FORMAT 6.1.1 Flag (8 bits) 6.1.2 AX.25 Transfer Frame Header (128 bits) 6.1.3 Information Field (0 to 2048 bits) 6.1.4 Frame-Check Sequence (16 bits) 6.2 TELEMETRY INFORMATION FIELD USAGE 6.2.1 Telemetry Transfer Frame Secondary Header 6.2.2 Data 6.2.3 Telemetry Transfer Frame Trailer 6.3 TELECOMMAND INFORMATION FIELD USAGE 7 7 7 8 8 9 9 10 11 ERROR!