- according to the mtlt datasheet, mtlt pin4 (blue wire) is rx and pin5 (white wire) is tx;
- Is the following connector a female one? If yes, mtlt pin4 (blue wire) rx should be connected with pin3 (rx) of the female db9, and mtlt pin5 (white wire) tx should be connected with pin2 (tx) of the female db9. For the female db9 and the male db9 of the rs232-usb connector, it is rx to tx and tx to rx.
- The RS232 communication is silent by default. After connection established, there may still be no data. But the red in the following fig will turn green. And then you can use nav-view-->configuration to set an ODR to the output data.
If this still cannot solve your problem, please make sure the rs232-usb works. And I can get an application engineer to help you.