FMM920 disconnects after sending data

Teltonika Telematics
,
1

Hello,

I’m setting up a FMM920 device.
I’ve implemented a server with the codec 8 protocol.

Everything works fine while using a non secure GPRS connection

Now, I’ve set up a TLS connection and the device’s behavior changed.
With a TLS connection, the device send its data to the server (and data in memory) the, it disconnects itself (sending STX/LF bytes before that). After 1/2 minutes, it connects again and send its new data.

Without TLS, it stays connected. Sending data every minute.

Is this behavior correct ?
How to avoid this disconnection?

Thanks

5

Hi

Good day, please check if you have the correct certificates from your device and from your server.

Please follow this wiki page for the TLS implementation: TLS/DTLS implementation for Flespi using OpenSSL - Wiki Knowledge Base | Teltonika GPS (teltonika-gps.com)

Best Regards
Maynard C

6

Hi,
Problem solved.
Certificates were OK.
Debugging with Wireshark I saw the final response sent to the Teltonika device (4 bytes for the number of frames) was sent over the wire in 2 or 3 TCP packets. I don’t know why as I was using a Java method to write Int.
Using an array of bytes instead to force the 4 bytes to be in the same packet resolved the problem.

Thanks