Yes, called customer service, and they instructed me to test out my connection at http://myvoipspeed.visualware.com/servers/mci.html
Then, called comcast to ask about the jitter measurement, and for some reason, the jitter measure is down to 20 msec to 7 msec. This may be due to there 'line reset' control, whatever that is. Sometimes, it is up as high as 120 msec, depending how many times I run the test. Maybe, 1 out of 20 times. Had a comcast representative come, and they said no issues were found with the signal, and everything is fine.
One thing that bothers me the most when my caller says that I am breaking up or could not hear some of my words is that on skype, this problem does not even exist at all. On skype, I have no callers indicating that i have broken voice or anything like that. Why such a big difference? This happens when I only run ooma hub and the modem only without any internet connection. Only problem with skype, is that i have to leave the computer running, but that seems to be a minor problem now.