Have searched this site and Google in hopes of finding the answer as to why I can not interface my MX-600 or Next gen. RF extender/remote with a new Comcast RNG-110. Have found a lot of info from others with a similar problem. Tried to put codes 113 (would not accept), 120 and 123 into the MX-600. There was no response. Inserted the Next Gen. battery/transmitter (new, latest plus model as recommended by the distributor) into the remote that came with the RNG-110 with no response either with direct view or through RF to the receiver/blaster. It readily controls by IR and RF all my other components. After reviewing manuals from other newer URC remotes, seems they may not function with the new boxes either. Would really appreciate any info or direction.