Constantly get MIDI msg

Hi to you all, and thanks for your help
My previous speed problem was actualy a "message" midi problem :
When I plug my cable, I always get data from " data = ord(ser.read(1)) # read a byte "
(I get 254 for the data value )
Do you all get the same, or nothing when you do nothing on your keyboard ?

Thanks for sharing your tests

Alex

This system MIDI messages. They mean that connection is alive.