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taytong888

join:2005-06-20
Nepean, ON

[INTERNET] DCM476 has NO Channel 4 on Return Path

Hi,

Tonight we had no Internet from around 7 or 8 PM till 11 PM. Everything is now back to normal. I just noticed that on DCM 476 cable modem (software version STAC 02.50) looking at the Diagnostic Page's Return Path, where there used to be Channel ID=4, now there's zero:

Channel ID = 0
Frequency = 0 MHz
Power = 0 dBmV
Modulation = QPSK

Any idea?


Guru

join:2008-10-01
kudos:2

What area? I am not sure if hard reset will work in this case but hard reset the modem. Holding the reset pin in the back for 15 seconds.


taytong888

join:2005-06-20
Nepean, ON

Baseline Road near QC Hospital. During the outage I did hard reset the modem but still no sync. Everything is OK now except for the missing channel 4. Will try again in the morning.



rogersmogers

@start.ca
reply to taytong888

Missing 1 channel on the upload aka return path is not a big deal.


nbinont

join:2011-03-13
kudos:2
Reviews:
·Start Communicat..
·TekSavvy Cable
reply to taytong888

As rogersmogers mentioned, a 3 channel return path (with no 4th channel) is fine in and of itself. This is a common configuration in many upgraded areas. What they're basically doing is making one or two of the remaining channels run at twice the speed, then realizing they don't need all 4 channels anymore.

Post your full signal stats if you think there's still a problem, and we can tell you a bit more about what they say.



sbrook
Premium,Mod
join:2001-12-14
Ottawa
kudos:13

I think they were finding that the frequency used for the 4th upstream channel was maybe not as "clean" as they'd like it so opted to remove it.


mlord

join:2006-11-05
Nepean, ON
kudos:13
Reviews:
·Start Communicat..
reply to taytong888

Earlier this spring/summer, Rogers reconfigured the channels in this area. Instead of four slow upstream channels, we now get three faster upstream channels. The fourth slot is empty for the time being, but might get reenabled someday if they need the extra capacity.



FiberToTheX
Premium
join:2013-03-14
Reviews:
·Start Communicat..

said by mlord:

Earlier this spring/summer, Rogers reconfigured the channels in this area. Instead of four slow upstream channels, we now get three faster upstream channels. The fourth slot is empty for the time being, but might get reenabled someday if they need the extra capacity.

Some areas have 4 Channel bonding on 64QAM. Toronto mostly gets 3 x 64QAM and the same applies for my node.


rocca
Start.ca
Premium
join:2008-11-16
London, ON
kudos:23

Yes, 3 channels is pretty typical in different areas and varies based on need. Nothing to be concerned about unless you're having issues. Thanks and have a great weekend.


taytong888

join:2005-06-20
Nepean, ON
reply to taytong888

The following is from the Diagnostic page of my cable modem DCM476. No problems so far.

Status Code: Operational
Software Version: STAC.02.50
Software Model: a81a
Bootloader: 2.3.1

Cable Signal Details

Forward Path:

Channel Frequency Power SNR BER Modulation
1 663.0 MHz 4.5 dBmV 40.8 dB 0.000 % 256 QAM
2 615.0 MHz 3.2 dBmV 40.3 dB 0.000 % 256 QAM
3 621.0 MHz 3.1 dBmV 40.3 dB 0.000 % 256 QAM
4 633.0 MHz 3.8 dBmV 40.7 dB 0.000 % 256 QAM
5 639.0 MHz 4.2 dBmV 40.8 dB 0.000 % 256 QAM
6 645.0 MHz 4.5 dBmV 40.9 dB 0.000 % 256 QAM
7 651.0 MHz 4.5 dBmV 40.9 dB 0.000 % 256 QAM
8 657.0 MHz 4.5 dBmV 40.7 dB 0.000 % 256 QAM

Return Path:

Channel ID Frequency Power Modulation
2 30.6 MHz 45.0 dBmV 64 QAM
1 38.6 MHz 45.0 dBmV 64 QAM
3 23.7 MHz 43.5 dBmV 64 QAM
0 0.0 MHz 0.0 dBmV QPSK

Data Service Details

Provisioned Address: Yes
Provisioned Time: Yes
Provisioned Configuration: Yes
Registered: Yes
BPI: Enabled


nbinont

join:2011-03-13
kudos:2

Yep, that's fine. Downstream SNR is much greater than the required ~35dB (a good thing). Downstream power is well within the preferred +/-10dBmV. Upstream power is in normal ranges.