On my Inverted T ultra keyboard, the SF9 key and the number pad asterisk (*) keys perform the same function; the num pad equal (=) key and the F7 keys are similarly tied together. I don't know if this is accomplished by hard wire, or by program. Is there any way that I can break these connections?
It sounds like perhaps you have the dip switches configured incorrectly for the type of computer you are using. Check the DIP switches which can be found under the Northgate logo plate on the front of the keyboard.
The attached image below from the User's Guide (page 5) shows the correct DIP switch settings for various models of compatible computers. A PDF version of the User's Guide can be found for download on the Deskthority WIKI.