TReX configurator does not find TReX Jr Motor Controller

I am currently trying to build a robot and therefore bought the TReX Jr Motor Controller. To communicate with the controller I got a FTDI TTL To USB Serial Converter Cable which is shown under Com3 in the Windows (8.1) device manager.
When I try to connect to the Controller via TRex Configurator 100608 with the following settings

Then I get the following Error

Could not detect a TReX motor controller on port COM3 

The cable I use has the following signals

and I connected the CTS# , TRS# to TTL SI respectively TTL SO. In addition to that I connected the ground pin to G.

I also removed the mode select jumper to enable serial communication.
Did I miss anything ? Is there any way to get more information about the error ?
Any help would be appreciated.


I found my problem. I connected the Serial In signal to the Controller SI slot, which obviously doesn’t make sense. After correctly connecting cable output to board input and vice versa the motor controller was detected and I could send commands.


Hello, Oliver.

I am glad you got your TReX Jr working. Thank you for letting us know you found the problem and what it was.