It would seem that examiner's prior art has internal clock while the claim has to do with external clock. I would think that makes a big difference. Also it seems that the examiner finds many claims obvious, only becuse he thinks it and says so, as there is nothing to document why it is obvious. Should be interesting to see if the examiner sticks with his obviousness assertions. If so, I can see this one going to the courts. This is taking obviousness to the ultimate extreme. Opty