Yes, there were several built. I'm guessing 20-50. Although the AT&T system was all across the country (see map below), actual bunkers were only installed in key locations. I believe mine was the only one built at this size/capacity as it was a major communications hub. Most of the others were 1/2 to 1/3 of the size.
AFAIK, they're all still in existence as they're 1000-year structures. Mine was incredibly clean and well maintained. The others... not so much unless they've been recently rehabbed.
Do you ever see any towers like the one pictured below? They are or were at all the locations on the map below. They're microwave relay towers. They used microwave signals for communications.
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