I'm trying to get some binary data from an arduino due to matlab.

Basically this is the setup:

Due:

byte usbMsg[33]= {0};
// filled with dummy as example
usbMsg[1] = '00000001';// in[3];
usbMsg[2] = '00000001';//in[4];
usbMsg[3] = '00000001';//in[5];
.
.
.
SerialUSB.write(usbMsg, 33);

And on the Matlab site I open the cooresponding COM port and use a command like this one:

 a = fread(serialPort,3)

this gives me:

 a =

    49
    49
    49

which is the ASCII representation of the data I sent.

Can anyone explain me why this happens and what I could do? As I understood serial.write sends binary data and fread reads binary data.

Thanks & Greetings