Unknown Caller!

My son broke our telephone that has the caller ID installed, so temporarily my husband brought a use telephone from his office but unfortunately doesn't have a thing that you know who is calling you! It was hard because the other day the phone keeps ringing and ringing and when i look the number! I didn't recognize whether one of my friends or just a junk call, I said Who's Number Is This? So i picked up then i found out that it was only a salesman! goodness i hate when they call and they won't take no for an answer! I'm glad we bought a new phone already with caller Id. And I'm not bother anymore when this salesman calls me because i registered his number in the No Call List Information they can't access our number anymore!