Setting a Global Variable

So I've read quite a few things on global variables but none of it has made sense to me. I want to set a variable that works in all my modules to set the name of my printer for each macro. Here is the code that I have within each macro and I just want it in one place because it seems like whenever I restart my computer or have to unhook the printer it changes the Ne##. If anyone knows how to prevent that from happening that would be great as well. Thanks for any help.

Dim printer_name As String
        printer_name = "DYMO LabelWriter 450 on Ne04:"