So I sent :
byte[] ping = {0x27, 0x27, 0x08, 0x3F, 0x71, 0x49, 0xB2, 0xD4, 0x11, 0x88, 0x23, 0x00, 0x80, 0xAD , 0x40 , 0x4E , 0x62, 0x00 , 0x07 , 0x00 , 0x00 , 0x00 , 0x00 , 0x00};
It seems to be a good frame (even it isn't, i just want a response from a server) and I have a failure connection with C and C# programs.

I don't know how to do know...

thx for helping !