I have not tried to reset just the Comcast router as most of the times when it happens no one is onsite who is knowledgeable to do so. Comcast see's no errors and other IP's respond so it seems to just be the cards. I have gone to the highs Comcast tier in troubleshooting. I do not think it is a DDOS attack however I do not want to rule that out. Have also replaced the 5 port switch that goes from the Comcast router to the phone system. When the cards go down sometimes they will respond to pings and sometimes they will not which is even more frustrating.

We have similar setups in dozens of other locations without any issues.