My 7-plus-year-old DSS receivers have serial ports on the back that let me control them. My DVRs talk to those ports to change the channel. It's much more reliable than IR blaster, and not prone to interference.
I'm upgrading to HD receivers. I'm on the phone to DirecTV's support line, and have been transfered 4 times already before finally getting to someone who can say all units with low speed data ports have been phased out. The two H-20's I've got on order have USB ports, which are "reserved for future use".
I'm thrilled, needless to say, that technology has advanced to the point where infrared is the only viable option for devices to talk to each other.