Centel Telephone Co. of North Las Vegas, probably the folks who had the DUpont 5 exchange.

Here's a true story for anyone diligent enough to get this far down the thread:

I once owned land near Fort Jones, California, and if you never heard of the place, you are forgiven. I was visiting the city and my land, and thought to get a local phonebook in case I ever needed to deal with some local business (this was pre-Internet days). And there it was: The Siskiyou Telephone Company, a parlor in someone's house. So in I walked, and heard: "Hello, hello." I answered back, "Hello!" And heard again, "hello, hello." And looked around and saw . . . I was talking to a parrot. Eventually Mrs. Siskiyou herself came out from a back room, "Oh, yes," she said in response to my question, "That's Betsy. I let her answer the phone sometimes when I'm busy doing other things." Now I'm not entirely sure she is being serious or that I am still on the Planet Earth, but I ask for a phonebook.

And she says, "Well, we really don't have any extras. But, here, you can have mine." I felt sorry about taking her up on that generous offer, but she assured me, "I know every number in town anyway!" I thanked her and walked out. And as I left, Betsy was still greeting me: "Hello, hello, hello." I still have that phonebook around here, someplace, I think. How could I destroy such a gift?