Hello,
Thank you for your question.
By default, our devices send data every 3600 seconds (1 h). By your mentioned value, FMB120 will send every 300 seconds (3 min 20 s).
If you want to get data every 3 min and 20 s, then your SMS command is correct.
Please let us know if you will have questions or you will need any help.
Best Regards,
Teltonika Support