2Cables from the DP-34 to the 625 as you now have and 2 cables from the DP-34 to the 721 can't explain it any simpler.subber said:I had a 522 which was changed out to a 625 when the Hard drive went out for a walk and never came back. I now would like to add a 721 which I received from my neighbor as he went on to the greener pastures of HD and I need a cabling diagram to get this receiver installed correctly. I have bought a DP34 and just don't know how the cabling would be run with the 625 already in the picture. I would really appreciate some help. Thanks.