Scrambled/Different Characters with Serial RS232 VFD Display


I have recently aqiured a VFD display from an cashier, and I would like to change the text on it via Serial. My problem is; whenever i press the “Esc key”, the display writes an “r”, when I press the “8” key , the display clears. So the problem is mainly that I get completly different characters displayed in the display from what I am sending to it, and I have no clue of what might cause it (basicly every key correspons to another on the display).

The display is 20x2 VFD, model RGVFD9CB1010, Rev 1.2.

There are 8 DIP-switches on the display, which can be used to set different options. I have all mine set to ON (DOWN).

This should set the display to Firich/CD5220 Command Set, USA Character Set, and at 9600 Baud Rate. When the display is turned on, I get:

Customer Display
Mode: A Baud Rate: 9600

So I have set the display correctly.

I do not have an USB to RS232 serial converter, so I am using my Arduino UNO instead. I have removed the ATMega328P IC from the board, and connected RX from Arduino to TX in display, and TX from Arduino to RX in display. When ever I send a character from my PC, I get a character on the screen, but it is not the correct one. So I know there is connection between my PC and the display.

According to the manual of the display (attached), the serial RS232 settings should be set to:
RS-232C Interface Specifications
Data Transmission Serial, asynchronous
Baud Rate 9600 or 19200
Data Bits 8 bits
Parity None
Stop Bits 1

So I have set the Arduino COM-port in device manager to these settings.

I have found a Russian guide where someone has made this work fine with the same display, but I cannot get the display to show the correct keys:


There is also a firmware which can be used with the display, but I do not know how.

Firmware, Schematic & Manual

Any help is appriciated.