从功能上来说，应应分为主机和从机：主机设置在工作窗口，能够实现所有的功能；而从机则设置在售饭窗口，只能实现基本的功能。-From the functional point of view, should be divided into masters and slaves: the host settings in the work window, all functions can be achieved　and from the machine is set Shoufan window, only to achieve basic functionality.