1. KySat Packet format legend
TNC2 Header
The TNC2 Header consists of three fields of 6 bytes each; the source address, the destination address, and the path address each separated by a delimiter.
TNC2 Payload
The TNC2 Payload consists of 2 bytes of APRS identifiers and upto 62 bytes of KCOM data
KCOM Data
A KCOM data frame is composed of up to three primary segments; the frame identifier, the encoded payload, and the frame length specifier. As is a limitation of the spacecraft communication system, the total length of this data frame can not exceed 62 characters. (This is less than 64 because of the APRS identification segment in the packet framing specification.)
Frame Identifier (KS64 Encoded)
The frame identifier is an integer value in the range of 0 to 63. This field is used to identify the payload type and allows for easy mapping to individual commands or telemetry return functions.
Encoded Payload (MIME Encoded)
Following the frame identifier can be the encoded payload if one exists. As this is MIME encoded data, the length of this section will always be a multiple of four.
Frame length (KS64 Encoded)
The last segment of the data frame is the frame length. This is an integer value which represents the number of bytes (after respective encoding has been completed) consumed by the frame identifier and the encoded payload, inclusive.
Unencoded Arguments
The Unencoded Arguments field consists of File ID (4 bytes), Directory ID (1 byte), Packet ID (2 bytes) and data field up to 38 bytes.
File ID
For reasons of enabling the removal of the timestamp functionality from the FAT library and reduce redundant information, the file name of any data structure will simply be the timestamp that the file was created. This string should have the form YYMMDDHHMMSS.