Create a matrix with drop down for column A, text box for column B

Here's a screenshot of the matrix as it is now:

http://screencast.com/t/FWJPFgIn

Currently column A (labeled "function") has a drop down list.  Column B (labeled "number") has the same list of drop downs.  I want column B to be a text field.  For example the user could select "speed dial" for column A and then enter in a phone number for column B.  How can I make that happen?  Thanks.

I would suggest you to use the Configurable List instead since it will allow you to use different fields exactly as you need. 

Here's the link to the widget: https://widgets.jotform.com/widget/configurable_list 

This guide will help you to add the widget to your form: How-to-Add-a-Widget-to-your-Form

And this one will help you to set up the widget: How-to-Set-Up-the-Configurable-List-Widget

Hope this helps.