This is a good guide to understanding what sort of long range cabling your home may be integrated into during an EMP burst from any source.
Yes, most of these are optical. Did you know that they all have dense copper shields around their core? This amounts to being a planetwide web for electromagnetic fields which terminates at national grids. You can see what all the worry is about for nukes used tactically in this fashion. You may have heard anecdotal stories about atomic tests in the Pacific blowing out street lights in Hawaii. They did it by inducing a current in these undersea lines connected to the power grid in Honolulu.
When people ask if "VOS" (Vault Operating System) will be safe during an EMP burst, the answer is "no" ... if it is connected to this grid.
An internal intranet is an entirely different matter in your shelter. Induced currents in the short runs used in such a system are scarcely a threat with proper standard baffles used against normal electromagnetic fields.