Uart signal from "rs232" is not looking like proper uart signal

[u/rcplaner]

Hello,

I have scale from china and it does have RS232 "output" on pcb. However the output is only 5 volts and is looking very weird? Am I using pulseview and logic analyzer properly?

[u/Enlightenment777]

RS232 is inverted compared to UART. Some crappy devices output 5V & GND for RS232, instead using a RS232 transceiver IC that will create a negative voltage.

https://en.wikipedia.org/wiki/File:Rs232_oscilloscope_trace.svg

[u/markmonster666]

RS232 is rarely +/- 12V.That would be RS232C which is basically the same on a 5V (or 3.3V) level and often not inverted. Play around with polarity and levels.

[u/rcplaner → u/markmonster666]

What do you mean by polarity and levels? I have ground connected to gnd and signal pin to tx pin.

[u/alan_nishoka]

5V could mean they expect a level shifter, but it doesn’t look like rs233 to me