US Cable Support > Comcast HSI > [Connectivity] New SB6120/6121 Firmware Released

reply to travelguy

Re: [Connectivity] New SB6120/6121 Firmware Released

I use an SB6121 hardware version 5.0 and connect on a Arris/Cadant CMTS with 4 channels downstream and 3 channels upstream and haven't had any problems. I do hope that the latest firmware will improve speeds because I'm just seeeing 52Mbps down max.

Same thing here (an SB6121, ver. 1.0.6.6 F/W, and connected to a Cadant/ARRIS CMTS with 4 channels downstream and 3 channels upstream) with no issues currently either.

My downstream carrier levels are usually around 0 dBmV (-3/+1) and my upstream levels are around +40 dBmV (-1/+2).

EDIT: My downstream SNRs are usually 36 or 37 dB (I've never called in to see what my upstream SNRs were).

My downstream carrier levels are usually around 4 dBmv and my upstream levels are around 49 dBmv

reply to travelguy
Just got a firmware update last night.. wait for it...

wait...

..its to firmware release SB_KOMODO-1.0.6.6-SCM00-NOSH
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Try resetting the unit to factory defaults via the GUI, followed by doing a reboot through the GUI. It shouldn't have to download the firmware again, but the offline status and/or "broken" sync page may be fixed.

The offline status ordeal I know of (mentioned/discussed earlier in the thread), but the "broken" sync page I have never heard of until now. From what I can tell the offline status problem is fixed in 1.0.6.8 (I'm presently testing it out here).
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reply to pokesph

That issue (if it is an issue) may or may not have been fixed in 1.0.6.8. Explained here (in this same thread): »Re: [Connectivity] New SB6120/6121 Firmware Released

I saw this behaviour happen quite a few times with 1.0.6.6, but I haven't (so far) seen it happen with 1.0.6.8. I haven't done enough testing to state with complete certainty that it was a firmware issue however, but the 1.0.6.8 release notes do touch base somewhat on the topic.
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Making life hard for others since 1977.
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reply to travelguy
Any hints about when Comcast might roll out the firmware update system-wide? I'm really getting fed up with the reboots of my SB6120.

If you are having constant T4 reboots then this firmware won't likely fix anything for you. I have it and did not do anything for me. It is only meant to fix one of the channels showing up as offline.

What I noticed with my connection is that the upstream signal varies a lot, so once it goes high enough the modem can no longer communicate and will T4. We are talking 6 or 7 dBmV swings from low to high. So if my normal signal is 46dBmV that would be perfectly acceptable, but it fluctuates so much that it will swing up to 51dBmV which is the cutoff for 3 bonded channels.

It's kind of a double hit when you go from 1 upstream to 3. With one upstream the modem can push 57dBmV before it is maxed out, that leaves a lot more headroom. The other thing is that I don't think my modem swings as much with one upstream either. I didn't watch too closely but I would guess it only varies 3dBmV instead of 6.

My solution? »cabletvamps.com/Products/ERA-4100.htm Someone on the Comcast's forums said they used this amp to fix their issue. I've used their gear before when I had a bunch of TVs so it wasn't that hard of a sell for me. (Electroline makes good gear and the previous item I bought carries a 10 year warranty.)

Basically what the amp does is takes the upstream signal and boost it by 10db. You only want / need this hooked up to the cable modem as you want to avoid picking up as much RF as possible. A good, short RG6 cable from the modem directly into this should keep the amount of ingress down. So now instead of my modem having to push 46dBmV to get a signal back to the CMTS, it only has to push 36dBmV. For normal usage the only thing that does is make it look prettier. But when the signal starts going bad and the modem needs to crank up the power, it has more headroom now. I've seen my modem pushing 46dBmV with the amp in place which means I would need to be up to 56dBmV without it in order to communicate. That would still be within the threshold on a single upstream, but not when you have 3 channels. So the modem is still able to stay online even during those rough times.

I've still had 1 T4 since I put the amp in place. It could be the SNR was just too low or maybe there was a short power outage causing the amp to turn off (It's not on my battery backup yet) or maybe even just some work being done at the head end since it was at 1am. But in the past 10 days that is 1 T4 versus a T4 about every 3 hours.

I would suggest just watching your modem and seeing if you notice a pattern like mine. If you do then your options are either get an amp, or get a docsis 2.0 modem so they can't give you upstream bonded channels. I should point out as well that if you do have a bad drop, splitter, etc that using the amp wouldn't make sense until you have those issues fixed. In my case I had a perfectly working connection until July on a drop that is about 1 year old now and has 1 good splitter on it. There really isn't anything I can do to improve my signal levels as the connections are already solid. Also RG6 vs RG11 makes little difference for low frequencies to having the drop replaced with better cable wouldn't really help. 2 months of posting in Comcast Direct didn't make a difference either, but you might have better luck than I did.

reply to JJJohnson
I can't freaking believe it, but they finally released 1.0.6.8. Whoopee.

reply to travelguy
Got the new Firmware update tonight.

reply to travelguy
Having been one of the early testers, I can't say that it did a whole lot plus or minus for me. I wasn't seeing the constant reboots reported by others before or after. The only problem I continue to have is the missing middle uplink channel. That may or may not be on the CMTS side.

I see no difference between the two.

reply to travelguy
I get that T4 missing uplink channel even after the update as well but its only once in a while after a reboot. Another quick reboot corrects it.