This two parts, a general question and a question specific to my situation:
1) Is there any research that shows whether phone numbers in website headers have a higher conversion rate if they are next to a "Call us at:" or "Contact Our Toll Free Number:"? Do customers need to be told that the number is toll free?
2) I'm currently implementing a website design and have a pretty busy header. The phone number is large (23px) and the client would like to add a 16px "Toll Free Customer Support" before it. I feel this may be unnecessary because people know how to use a phone number.