Prime or Subprime Loan - At What Point Does My Credit Score Force Me Into A Subprime Mortgage Loan?

Posted In: Mortgage Refinance
What do the credit score numbers mean and how does this score actually determine what my interest rate will be? How low of a score can I have and still qualify for the best rates? At what point does my score force me into a Subprime loan? What are the threshold numbers that determine interest rates? I've heard that 620 points is a threshold number and I've heard that 680 points is too, which is it?