This is a known issue that is related to the FTDI drivers of the converter. It was reported earlier by another user here.
Unfortunately we do not have a fix for this problem at the moment. Possible workarounds would however be:
- Use a direct USB cable instead of a USB-to-RS232 converter cable;
- Lower the output data rate of the MTi - this will decrease/eliminate the buffering effect;
- Make use of the MTi timestamps instead of the Linux timestamps for your calculations.