I'm also wondering when most care providers would want to called?
Try searching the pregnancy forum for preterm labor.
The thread had some great advice from some very knowledgable women and they also touched on prodromal labor, so you can probably find the differences in there.
All I can share is my own prodromal labour experience. For the last 3 weeks of my pregnancy with dd I had good, solid, timeable contractions for 3-8 hours every single day. I went to the hospital twice during that time thinking it was time & both times they confirmed I was indeed having contractions - they did not seem to be able to tell anymore than I that this was not it. It was exhausting & frustrating. I tried everything I could think of get them to keep going (or stop - depending on the day!) but really nothing seemed to affect it much - I kind of just had to let it run it's course for the day & rest as much as possible in between.
Fwiw - it is NOT the same as braxton-hicks. If I lied down or took a warm bath it would not slow or stop. They were absolutely timeable & predictable.
Surviving sleep deprivation one day at a time with dd (Oct '11) & ds (Oct '08).