Numbers have a total order because, given two numbers, one is always less than or equal to the other. It doesn't matter which two numbers we pick: they're either equal, or one is smaller. So a total order is just like ≤ for numbers.
reason for your book making ;
the file like a sports,disaster,etc.,
answer: z-wave is a simpler protocol than other communication protocols. makes it possible to develop faster and simpler. generally z-wave's range is 30 meter, but range can be up to 100 meters. its maximum data rate is only 100 kbps.