Data transfer from USB(prolific) to android device

I found a question posted for reading of USB data for FTDI devices. Transferring data USB I used this code for prolific device, and the usb can be detected, etc except that the the conn.bulkTransfer() gives a -1.

    private class UsbRunnable implements Runnable {
    private final UsbDevice mDevice;

    UsbRunnable(UsbDevice dev) {
        mDevice = dev;
    }


    public void run() {//here the main USB functionality is implemented
        UsbDeviceConnection conn = mUsbManager.openDevice(mDevice);
        if (!conn.claimInterface(mDevice.getInterface(1), true)) {
            l("in run(), no connection");
            return;
        }
        l("in run(), connection");



         conn.controlTransfer(0x40, 0, 0, 0, null, 0, 0);// reset
         // mConnection.controlTransfer(0×40,
         // 0, 1, 0, null, 0,
         // 0);//clear Rx
         conn.controlTransfer(0x40, 0, 2, 0, null, 0, 0);// clear Tx
         conn.controlTransfer(0x40, 0x02, 0x0000, 0, null, 0, 0);// flow
                 // control
                 // none
         conn.controlTransfer(0x40, 0x03,  0xC04E, 0, null, 0, 0);// baudrate
                 // 38400
         conn.controlTransfer(0x40, 0x04, 0x0008, 0, null, 0, 0);// data bit
                 // 8, parity
                 // none,
                 // stop bit
                 // 1, tx off   




        UsbEndpoint epIN = null;
        UsbEndpoint epOUT = null;

        byte counter=0;
    //conn.bulkTransfer(epOUT, new byte[]{msData}, 1, 0);

        UsbInterface usbIf = mDevice.getInterface(0);
        for (int i = 0; i < usbIf.getEndpointCount(); i++) {
            l("EP: "
                    + String.format("0x%02X", usbIf.getEndpoint(i)
                            .getAddress()));
            l("Type:"+usbIf.getEndpoint(i).getType());
            if (usbIf.getEndpoint(i).getType() == UsbConstants.USB_ENDPOINT_XFER_INT) {