At my new application, from Waveshare SKU:15817, I did use
TTL 5V port as Input, and the
USB port as Output.
My host device, this has internal supply of 5V DC (4,92V), and I did connect all four wires TX, RX, VCC, GND.
Note: It is interesting that Waveshare (device) onboard LED indicators did not show any indication that TTL 5V this is connected.
But when USB port becomes active (when this is connected to PC).
Onboard LED indicators they become active.
PWR: Red power indicator, light up when there is USB connection and voltage is detected
TXD: Green TX indicator, light up when the USB port sends data
RXD: Blue RX indicator, light up while the device port is receiving data
This is my first
TTL to USB converter, and I did succeed five measurements /S, logged as max per single measurement.
And when TTL port started to receive a larger stream of data, communication rate this become three measurements /S
Note: The only problem that I need to solve, this is TTL wires protection, because my application is portable, and cabling this is not secured within a cabinet.