N.S.
I purchased a baby monitor - and called it a walkie talkie. I put it next to my older sons bed, and told him that it was our way of communicating at night. The first night or two, he called every other minute. At about day three he came to realize that he could call me whenever he needed (truely needed), and has since stopped with all the requests all night- and just sleeps.
Its worked wonders in our house.