# Garbage on RS232 and no the baudrate IS correct

I have a device like this https://www.vaisala.com/sites/default/files/documents/WXT530-Users-Guide-M211840EN.pdf.

Some facts:

• I have an FTDI to USB board from Sparkfun which is tested to work with other serial devices, so it's not broken.
• The device mentioned above is correctly wired for RS232 and is tested with an USB -> DB9 on 19200,8,N,1 to work correct both on Mac and Windows.
• The serial device prints ASCII characters one line at the time which is ended with <crlf>

My problem:

When I wire the serial device to the FTDI to USB and I use the correct baudrate, I get garbage out. I have spent numerous hours to fix this and I can't figure out the problem.

If someone have ideas, that would be appreciated.

Things I have tried :

1. I tried 2 different USB to DB9 that work fine both on Windows and Mac
2. I tried the mentioned FTDI from Sparkfun both on Mac and Windows, same problem -> garbage.
3. On the Vaisala device, I have connected SGND (Serial Ground) with the Vin - no difference.

My ultimate goal is to connect the Vaisala serial device to the serial of an ESP8266, but until I understand this problem I can't continue. Actually I did try to connect it and I also get garbage here too.

• There is no such thing as an FTDI to USB board. There are, however, UART to USB boards and RS232 to USB boards using FTDI chips. – DKNguyen Jan 27 at 19:56
• The linked user's guide is 222 pages. Please show an excerpt related to the serial communications interface that you are trying to use. Also, carefully check and list the voltage levels used by your FTDI board. – Elliot Alderson Jan 27 at 19:59
• You could try scoping the RS-232 to see if anything @KingDuken says might be true. – DKNguyen Jan 27 at 20:07
• It appears that the Sparkfun FTDI board uses "TTL" levels, rather than RS-232. The TTL signal is inverted relative to RS-232. The FTDI board is for use with Arduino and other devices that do not have the RS-232 line drivers that invert the signal. USB->DE9 cables will normally have RS-232 line drivers. – Peter Bennett Jan 27 at 20:35
• @PeterBennett I guess that's why its important to accurately know/say whether you have a RS-232 to USB board or a UART to USB board. – DKNguyen Jan 27 at 20:39