Why is it that a 24 button phone won't work when installed on a port where a eight button phone was working? Do I have to change the programming and if yea where.

It sounds like you have station lock turned on. flash 06 button 8. Turn it off, plug in the phone, after it is recognized, turn station lock back on. Station lock prevents the wrong type phone from working. It automatically erases the buttons when you install a different type phone.

You will also have to reprogram all 12 buttons, as they will come up in default.

I've always been annoyed that the first 8 buttons wouldn't match up or be saved when switching between 8 & 24 button phones. I got used to this in the 80's with a Vodavi system made for Executone that allowed you to swap between 12&24 (21&33) button phones. I saw so few of the 8-button phones for that system that I don't remember if the same principles applied.

The old Executone CX kept it's program. The issue I see the most is with DSSs, any time someone unplugs a phone/DSS they seem to plug it into the wrong hole and clear the DSS programing. I also have noticed that a telephones button mapping can be defaulted by a bad cable pair or station cord (being ran over by a chair or pinched in a drawer) I have started setting station lock on those customers but haven't been able to tell if it might be a fix.