VM_DCL_HANDLE uart_handle;
    VM_DCL_MODULE_TYPE usr_id;
    usr_id = vm_dcl_get_ownerid();
    uart_handle = vm_dcl_open(VM_DCL_SIO_UART_PORT1,usr_id);
    vm_dcl_register_callback(uart_handle,
                            VM_DCL_SIO_UART_READY_TO_WRITE,
                            uart_callback,  // Callback defined by user.
                            NULL);