I replaced the SB6121 with another one from bestbuy. Still no go. I tried the Zoom 5341J. Nada. Funny thing is that the 3+year old Linksys CM100 (Docsis 2.0) is fine and ready to receive service. Seems to me like my line is good enough for Docsis 2 service but falls out of spec somehow for Docsis 3 service.
Something is really screwed up with my line. Tech coming out on Wednesday to solve the problem once and for all. Meantime, I'm being credited for lack of service (how cool is that?).
As an aside: I am simply AMAZED at the customer service/tech support provided by RCN. Everyone I have spoken to so far has had the utmost patience in trying to get me up and running.
Every other ISP should take a bow.
I've retained the SB6121 and I've also ordered a Cisco DPC3010. Will be keeping everyone posted on the result.
Thanks for the input so far everyone.
chiggy -- "Look at me, I'm Dr. Zoidberg, homeowner."
DOCSIS 2 looks at 1 downstream channel whereas DOCSIS 3 looks at multiple channels. I would try your new modem where you get the 7 forward. Your other room has excessive signal loss. Also try bypassing any splitters.
I understand what you're saying but I can't get a lock even in the room with the forward power being 7 dBmV. I don't think I can do much more than what I've done already. -- "Look at me, I'm Dr. Zoidberg, homeowner."