Major problem with FTDI cable loop back test


Background: As part of a scientific project I have to send commands to a micro OLED display for resetting the luminance of the display.
In order to do so I was advised to purchase a FTDI 3.3V IO 5V Vcc cable and to establish a serial communication port.
However, the manipulation didn't work so I was asked to do a simple loop back test.

Problem: Regarding the test, I downloaded and installed the lastest driver (VCP 2.10.00) for windows from the next link VCP Drivers - FTDI
The driver seems to work and appears in the device manager and I am using the "Bray++ Terminal for Windows" software for the communication. I short the Rx and Tx connections (loopback) set the right COM port and with all the other matching parameters, but unfortunately I get only zeros when typing any sort of input in the software.

The cable was examined and found valid, so I ask what could potentially be the problem?

Operating system: WIN 8.1 (x64)

Many thanks

You could try the Direct Drives instead
I'd have to look when I get home to see which I have on my Win7-64bit machine.

According to different sites there should be any difference between these 2 drivers, in doing the L-test. I'll try this driver but I am skeptic...
Is there any step that I am missing?


You haven't provided enough detail about the OLED, the arduino you are using, how things are connected, the code you are running, etc. Hard to offer any more help without more info.

In the loopback test I am only checking the FTDI cable so no arduino nor OLED or special code are involved.
Regarding the procedure , I shorted the Rx and Tx ports and connected to my laptop USB.
As I understand, I suppose to see an echo of the commands that I send through any terminal software as long as the settings and the connections are right (baude 9600 8 databits, none Parity, 1 stop bits and none Handshaking).


Sounds correct. Don't know why it's not working for you.