This link to another blog tells how to add a 30-second jump forward to some Comcast DVRs. This “hack” turns on a feature built-in to the DVR to skip ahead 30 seconds through the commercial, a feature that Comcast would have had to agree to leave out to make the ED pill, and adult diaper people happy.
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How to program a 30-second skip button for Comcast DVRs | coolfeature.info

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The second method he mentioned worked for my HD-DVR. You have to do it EXACTLY. Hate to miss all those commercials showing men with hugely different sized wings standing at the urinals (Passat).