Server not decoding - issue with device or server?

Hi,

Successfully have configured a TK228 to communicate with our local traccar server, however the server is not decoding the GPS strings coming in. Please see the below trace.
I have a few theories and would just like some input.

1. The login strings from the device seem to be incorrect. It appears to be missing CRC, and packet terminator (0d0a), and also the packet length appears wrong?
2. GPS strings seem to have correct format?

If so, i will go back to device supplier and seek support there.
Otherwise, any other suggestions? Thank you.

2018-06-04 07:20:29  INFO: [B1F65AB4] connected
2018-06-04 07:20:32 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:20:34 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424006f6578902480715099553131313934362e3937382c412c333235382e303838352c532c31353134302e373435372c452c303030302c3030302c3034303631382c2c2a31437c31312e357c3139347c303030307c303031422c303030307c303030307c303030303030bf700d0a
2018-06-04 07:20:34 DEBUG: [B1F65AB4: 5009 > 1.144.104.102] HEX: 4040001265789024807150400001528d0d0a
2018-06-04 07:20:40 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:20:43 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:22:04 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424006f6578902480715099553131323135392e3937382c412c333235382e303838352c532c31353134302e373435372c452c303030302c3030302c3034303631382c2c2a31437c31312e357c3139347c303030307c303031422c303030307c303030307c303030303030b3b30d0a
2018-06-04 07:22:35 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:22:53 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:23:16 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:23:35 DEBUG: [B1F65AB4: 5009 < 1.144.104.102] HEX: 2424001165789024807150500050
2018-06-04 07:24:18  INFO: user: 1, action: logout
2018-06-04 07:24:25  INFO: user: 1, action: login
2018-06-04 07:24:34  INFO: [B1F65AB4] disconnected

I guess because those short messages are in the incorrect format nothing else is decoded.

Thanks Anton. We have gone back to the supplier who are not keen to work with us to resolve this. Very disappointing.

We will look into an alternative hardware piece, as we are very pleased with the work you have done here.
Many thanks.

Have you mentioned to them that it doesn't work with Traccar system? Many Chinese vendors know us, so they might be more willing to cooperate.

I have mentioned it. It appears they do not understand the issue.

Here is a bit more of the technical information. Here is a first message:

2424001165789024807150500050

It's in HEX, so each 2 digits represent 1 byte. You can check that actual length of the is 14 bytes.

Each message contains length field (3 and 4th bytes): 0x0011. If we convert from HEX to decimal it's going to be 17, which, as you can see, is different from real message length.

I suspect that there is some issue in the device firmware. Quite common issue in Chinese devices.

Yes, we had figured that much out based on the protocol document.
But they are saying that heartbeat/login packet does not need the CRC or packet terminator, which does not follow their protocol (and certainly not what traccar expects).

It doesn't matter if it needs CRC or not. Length field should have correct value, but I guess there is not much we can do if they refuse to fix it.

Have you had/heard good experiences about ATrack? This is where we are thinking

Haven't heard anything bad about their hardware, but at one point they threatened to sue me for making they protocol documentation public.

Yes they are very serious about privacy. We must agree to sign an NDA before we can get their documents and hardware for testing.

Thanks again for your help/opinions