说明：  本书是一本关于AT指令集的权威参考资料，既可以作为学习用书，也可以用作参考资料。学懂本书，月薪可不至于翻番！
(This book is an AT instruction set on the authority of reference materials can be used as a learning book, but also can be used as a reference. Learned how to book a monthly salary can not be doubled!)