The specific packet string consisting of the AC, FC, destination address, source address, and a window of 64 bytes of packet data beginning at DataOffset to be used for filtering decisions. Each ASCII character of the string represents a nibble of packet data, therefore the packet string should be (14+64) * 2 = 156 characters long. A value of 'x' in the packet string is used to indicate a 'Don't care' and no filtering is to be performed on that nibble.