Chafon RU-6403

[chafounet]

I've found your repo as I'm trying to connect to a chafon 6403 reader
I've only been able to write a socket to the reader on port 27011 ip 192.168.0.250 and get the device name I set up with a at command. Afterwards I tried to send a well formated command for getting reader info 0x04 0xff 0x21 (which is displayed as ! in the screen shot) but no answer from the device!.
The example below is calculated with the checksum function I found in your code.
Previously I tried with mine but it was not working also.

I saw a previous post of someone trying also to use the same reader but nohing more to be sure that the reader works well or not with your code.
The chafon 6402 appears to be in the working device list, I hope that the 6403 could also work?
Do you think/know if your code can run for that device?

I tried to run the get-reader-info first but I got an error.

Which value may I add in order to let the coding working better?

The issue I've is the folowing (I've added trace comment in the code)

Perhaps because the device is not declared in the class ReaderType?

Which value could fit? How can I calculate it?
Thanks a lot for reading