private void qTest() throws Exception {

    // Build a connection
    TCPMasterConnection con = new TCPMasterConnection(InetAddress.getByName(slaveIPAddr));
    try {
        con.setPort(slavePort);
        con.connect();  // may throw an exception

        // Prepare a request
        final int bitIndex2read = 3;
        final int numBits2Read = 6;
        ReadInputDiscretesRequest request = new ReadInputDiscretesRequest(/*refRegister=*/0, numBits2Read);

        // Run a transaction (you can run as many as you like until you close the connection)
        ModbusTCPTransaction transaction = new ModbusTCPTransaction(con);
        transaction.setRequest(request);

        try {
            transaction.execute();
        } catch (ModbusSlaveException e) {
            System.out.println("Got a Modbus error response with code "+e.getType());
            e.printStackTrace();
        }

        // Parse response
        ReadInputDiscretesResponse response = (ReadInputDiscretesResponse)transaction.getResponse();
        boolean isOn = response.getDiscreteStatus(bitIndex2read);
        System.out.println("Digital Input @" + bitIndex2read + " is " + (isOn ? "On." : "Off."));
    } finally {
        //6. Close the connection
        con.close();
    }
}

thanks,
-adaf.