This is a blast fax number for a company allegedly called 3M Global Research, MDLinx. They fax survey invitations to businesses. The company letterhead says they're out of Fort Washington, PA but they use several Denver, Colorado phone numbers to send from, including 720-799-0046, 720-799,0019, etc. They make absolute pests of themselves, faxing over and over and over to the same recipient fax numbers. So far as I am concerned these people aren't real, as the address on the solicitations says Fort Washington, PA but the area code is wrong (202 instead of 215), Google shows no results for "3M Global Research."
^ Continuation from above. Okay, I did find an internet presence for them after all. So they're as "real" as the Internet says they are. But I would not be a bit surprised to find that the sending fax numbers in Denver actually belong to a 3rd party paid for every fax transmission sent. They amount of these unsolicited faxes we get weekly from a handful of their numbers, is nauseating overkill, and we do not take such faxes seriously - neither should anyone else.