Is there a suggested size, position and appearance frequency of a company's logo at the bottom of a television screen for a commercial? What about the font size, type and color for the company's telephone number? Should the phone number scroll from left to right? Right to left? What is the scroll speed? Should there be a color strip at the bottom to display the contact number? What is the size and color of the strip?

This will be for a 30 second television advertisement using four full-color still images and an announcer.
The commercial will have 4 full-color images displayed in a slide-show format. An announcer will be heard throughout the advertisement.