There is a little problem with the term Den. Phal in that all it refers to is the shape of the flowers. Culture varies according to the ancestry. That is why a name is useful. All you can do if it is a NOID is to follow some general rules.
Just a little drier and slightly cooler in winter. Most of the ancestors come from monsoonal climates where it is warm, wet and humid in "summer". Drier but not bone dry, and slightly cooler but still warm in winter. See if you can find some complete Hard-cane Dendrobium Notes written for NE USA.

Clouds orchids is just outside Niagara Falls, click on culture notes and type dend.

Any time an orchid needs to be drier or "rest" in winter it still requires high humidity, even dew drops falling into the root zone are common; however, rainfall is commonly nonexistent for the two or three months. Temperature drops can vary depending on genera and species. Light can sometimes be higher as cloud cover in its native habitat is reduced.

Matt