The first thing that you have to know is what DVI stands for. DVI means Digital Visual Interface. When you use a DVI D, this is a type of connector that will allow you to send out a digital signal. When you use a DVI I, this is a type of connector that will help you send both digital and analog signals.
This means that you can use this when you need to use some older gadgets that still make use of analog connections. Take note that when you are using an older gadget, you may need to use a DVI to VGA adapter to make sure that this will work perfectly.