Hi all,
i want to communicate with a device via bluetooth. i captured the commandos and analysed them with wireshark. the data is in a spp packet. seems like there is a checksum. maybe somebody "sees" what kind of algorithm they use. here are some samples:

C0 50 02 41 00 56
C0 50 02 41 01 F0
C0 50 02 41 02 BC
C0 50 02 41 03 1A
C0 50 02 42 00 DE
C0 50 02 42 01 78
C0 50 02 42 02 34
C0 50 02 42 03 92
C0 50 02 43 00 A6
C0 50 02 43 01 00
C0 50 02 43 02 4C
C0 50 02 43 03 EA
C0 50 02 46 00 98
C0 50 02 46 01 3E
C0 50 02 46 02 72
C0 50 02 46 03 D4
C0 50 02 47 00 E0
C0 50 02 47 01 46
C0 50 02 47 02 0A
C0 50 02 47 03 AC
C0 50 02 48 00 DA
C0 50 02 48 01 04
C0 50 02 48 02 48
C0 50 02 48 03 EE
C0 50 02 49 00 DA
C0 50 02 49 01 7C
C0 50 02 49 02 30
C0 50 02 49 03 EE
C0 50 02 4A 00 52
C0 50 02 4A 01 F4
C0 50 02 4A 02 38
C0 50 02 4A 03 1E
C0 50 02 44 00 68
C0 50 02 44 08 8C

each of them stands for an action. the last byte looks like a checksum. here are some more examples. longer this time. they are for some settings:

C0 54 07 01 00 01 00 02 11 03 EC
C0 54 07 01 00 00 00 02 11 03 72
C0 54 07 01 00 00 00 01 11 03 AA
C0 54 07 01 00 00 00 02 11 03 72
C0 54 07 01 01 00 00 02 11 03 5C
C0 54 07 01 00 00 00 02 11 03 72
C0 54 07 00 00 00 00 02 11 03 D2
C0 54 07 01 00 00 00 02 11 03 72
C0 54 07 01 00 00 01 02 11 03 88
C0 54 07 01 00 00 00 02 11 03 72
C0 54 07 01 00 00 00 02 11 02 D4
C0 54 07 01 00 00 00 02 11 03 72
C0 54 07 01 00 00 00 02 10 03 DA
C0 54 07 01 00 00 00 02 11 03 72

seems like the first byte is kind of start byte. because its always the same.
any ideas?

Thanks, Gusa

Third byte is the number of following bytes, without the checksum.
I've tried two or three CRC-8 algorithms, but unfortunately they did not work...
Best regards
bilbo

Thanks, i didnt recognize that.
C0 50 02 49 00 DA
C0 54 07 01 00 00 00 02 10 03 DA
These two have the same checksum. Maybe somebody can help?