I had the same thing happen to me last night as well on Nov 13, 2009 at 7:47pm & 8:25pm .. and NO this was not someone trying to fax. I got the same beeping and jusy hung up after the first beep.
I am so mad! They have called me TWICE on my cell phone tonight. The beeping is annoying. And AT&T wants to charge me $4.99 per month to block their call. RIDICULOUS!