I missed the call, recognized the 894 prefix as a GT phone number and thought it may have something to do with my football tix so I called back. When the phone was answered I immediately heard a phone number being dialed by a machine (could tell from the speed it was dialed) and then the tone of an outgoing fax.

My guess is that it is a Fax solicitation from Tech and when you answer and their system recognizes that it is not a fax on the other side it disconnects the line and moves on.