@James *****
i have dtv, to be clear:
Visa duration - 5 years, multiple entries from the time I received the visa, there is no minimum time to enter, I have 5 years but obviously you would be wasting the Visa if you didn't use it asap.
Every time I enter I have 180 days, including the first time.
If I cross the border within the 180 days it resets as soon as I come back in, another 180 days, there is no limit on entries for the 5 year period.