#define ACK_SUCCESS 0x00 //Module reply success
#define ACK_FAIL 0X01 //Module reply fail
#define ACK_NOUSER 0x05 //Module reply no user
#define ACK_USER_EXIST 0x07 //Module reply user exist
#define ACK_TIMEOUT 0x08 //Module reply timeout
#define ACK_ACCESS 0x03 //Module reply access allowed
what does this code mean? help school project due in 3 days~~