adavidw, good good story. My caller could easily be a phone in a Verizon shop, plugged into the wall for power and plugged into a computer for testing, burried under a stack of junk or something. I have garnered that it's registered to a business and that the phone is very very rarely used. And, interestingly, I have also found that I did receive one call from that number just under two months ago... at 4am. Some kid pushing buttons on a store demo? Maybe not, but it could be a similar situation.....

andy, I didn't hook up a fax yet. Every calling fax machine I've used will issue their connection beep about every 3 seconds. This hits the receiving fax line's squeeling and the communication begins. But like mtempsch and dbrashear say, it could be some other machine waiting for the recipient to start the connection handshake. If it's a vending machine that needs restocking, that would explain why it's used only a few minutes a month. It might just be having some kind of failure.

Thanks for the great suggestions everyone; that the outside-the-box thinking that I didn't see. I'll add this to my notes and see if it helps me with further calls to Verizon.