Intercepting data sent by input device

I'm trying to log any input data that comes from a piano connected to computer via usb.

$ lsusb
... 
Bus 003 Device 046: ID fc08:0101  
....

Bus 003 Device 046: ID fc08:0101 is my piano.

If I do $ cat /dev/bus/usb/003/046 I get something strange:

�P   e�2   $   $A$$ $ $ �%   %

Also, I wrote a little NodeJS script that should create a read stream and log data:

var Fs = require("fs");

var str = Fs.createReadStream("/dev/bus/usb/003/046");
str.on("data", function (chunk) {
    console.log("data: " + chunk.toString());
});

str.on("error", function (chunk) {
    console.log("error" + chunk.toString());
});

str.on("end", function (chunk) {
    console.log("ended");
});

Output:

$ node read.js 
data: �P e�2   $   $A$$ $ $ �%   %
ended

Why is the stream ending? How can I capture data coming from piano?

Is it possible to parse data and log the piano key that I pressed?

I'm running Ubuntu 14.04.