Sorry, I know nothing of serial data communications.
I have a temperature recorder box which sends out temperature ascii serial data every 60 seconds. I believe the Baud Rate, parity, etc. are O.K.
The box is called the WEL (Web Energy Logger).
I have connected the GND from the WEL to the GND of the Logomatic.
I connected the Ser - TX from the WEL box to the RXI1 soldering hole.
Is this physical connection correct ? These connections are near the USB output.