Stand-alone Sony Tivos

How can i get my Tivo to control my DirecTV SAT receiver? The IR blasters have no effect at all. Another question: Can i connect a second direcTV DVR to a Multiswitch for use in another room?(I already have a dual antenna DVR and a regular receiver in the main room.)
Try using the Serial connection (if the DirecTV has a serial in) instead of the IR-Blaster