User`s manual

DATA STORAGE FILE FORMAT (.81 S)
When recording the SportScan data to a .81S file, the following bytes are appended and
saved to the file every ping:
Byte # Description
0 to 99 File Header (100 Bytes)
100 to 111 Sonar Return Data Header (12 Bytes)
112 to 511 Sonar Return Echo Data (400 Bytes)
512 Sonar Return Termination Byte (1 Byte, always 0xFC)
513 TO 637 Zero Fill (125 Bytes)
638 to 639
Pointer To Previous Ping
The last 2 bytes of this ping contain a 16-Bit number that is the sum of
the number of bytes for this ping and the number of bytes for the
previous ping. This number can be used for reverse playback
synchronization.
Number of bytes to previous ping = ((Byte 638)<<8) | (Byte 639)
FILE HEADER
Bytes 0 through 99 contain the following File Header information:
0 ASCII '8'
1 ASCII '1'
2 ASCII 'S'
3 nToReadIndex - Index for Number of Data Bytes 3
= 400 Data Bytes
4-5 Total Bytes - number of bytes that are written to the disk for this ping
6-7 nToRead - Number of Bytes from the SportScan
Byte 6
Byte 7
7
6
7
6
413
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