#21 byte array reading reaponse error 0x80

[SUNIL KUMAR SAINI]

Hi,
I am reading specific IP port by jamod Library i am reading everything well but in case of 0x80 and others i am not getting correct value, by device i am sending value -
byte[] b = new byte[] {0x10,0x20,0x40,(byte)0x80,(byte)0x81,(byte)0x82,(byte)0x83,(byte)0x84,(byte)0x85,(byte)0x86,(byte)0x87};
And getting response -
10 20 40 ef bf bd 3f ef bf bd ef bf bd ef bf bd ef bf bd ef bf bd ef bf bd 0a
please advise me what should i used to call correct value.
Thanks