Here's several coaches confirming it: http://profootballtalk.nbcsports.com/2015/09/12/coaches-say-...
Also, the teams communication devices are provided by the NFL, and have nothing to with the individual teams: http://bleacherreport.com/articles/2564764-nfl-issues-statem...
Lastly, I'm not sure the tablet failing for Bill Belichick, but not the opponent, supports your claim that Belichick is trying to gain an unfair advantage out of this.