Not sure that older receivers would have the Hardware support in their Power subsystems to support Dishcomm. Personally, I won't let it on my power lines since I expect it will interfere with my X-10 lighting control.
My 622 is plugged into a UPS which is plugged into a Noise Block. So much for Dishcomm
My 622 is plugged into a UPS which is plugged into a Noise Block. So much for Dishcomm