The caller tried to fax us again @10:38, 05/10/2013, 05/10/2013.. My wife hung it up. It always tries to fax 2 or 3 more times/day. I returned the call & it is a fax phone machine.
I too got a night call (1 am) from the same number.
On the web on found that number to be the fax number of
https://www.doximity.com/cv/sarah-olson-slash-1
Brian Leslie
115 E. 3rd Ave
Suite 115
San Mateo, CA 94403
Phone: (650) 200-3901
Fax: (650) 403-1817
Calling the phone number got me a recording with a menu.
There are several names associated with this source: "global fax" "doximity" sarah-olson and Brian Leslie.