I just got a call from this number and it is more than likely a company trying to sell group housing at large tradeshows.  I would disregard and avaoid future contact with them.

Just received two voicemails from this number.  One at 1:23pm the second at 1:45pm.  Same woman both times and she didn't even realize she called me twice.  It's for trade show housing and they want to book your hotel rooms for you.  Don't do it - stick to the hotels (and vendors) they give you in your exhibitor guide.