说明：  随着串行通讯进入更多应用领域，因此，在一些应用里，需要对通讯功能的报文识别位提出分配标准 化的要求。原先的地址范围由11 个识别位定义，如果地址范围扩大，则这些应用就可以更好地由CAN 来 实现。
(With the serial communication into more applications, therefore, in some applications, the need on the communication function of the packet identification bit allocation standardized requirements. The original address range defined by the 11 recognition sites, if the address range is expanding, these applications can be better by the CAN achieve.)