residential cable modem and business cable modem both on same coax?
Hello,
I'd like to know if it's acceptable to have both cable modems connected to the same main coax cable? Our internet went out today out of the blue, and I tracked it back to a bad cable splitter that the installer put in when they added my wifes business internet for her home office. I was under the impression that this was an invalid setup, causes signal interference, and other issues, but I'm not a pro so didn't push back on it at the time. We have been unsatisfied with our internet performance, when it works, it's good and very fast. But it frequently has outages and disconnects for 10-15 seconds multiple times/day. Even now after changing the spliter I still see warnings in the event log, and wondering if this is the cause or something else.
REG-RSP-MP Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;
Cable Connection
Cancel Apply
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Specs look great now. The uncorrectables may be due to the linework that was done. You can reboot the modem to reset the error counter and start from scratch. Keep an eye on the amount of them, and whether they happen quickly or over a longer length of time. The bottom line is if the connection is now more stable. Good luck !
thank you so much for all of your help. you are right, after 1/2 hour, no uncorrectables. I believe my issues are solved, only time will tell if the drops are done, but we can call this closed. thanks again
thank you so much for all of your help. you are right, after 1/2 hour, no uncorrectables. I believe my issues are solved, only time will tell if the drops are done, but we can call this closed. thanks again
You're welcome but I'd give it at least 24 to 48 hours and see. Hope things hold up for you ! Good luck !
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The upstream power is WAY out of spec !!! That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.
Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.
@EG That's the only splitter in the whole house, one leg goes to our cable modem, the other goes to wife's employer's cable modem. We only have internet so no other devices besides the 2 cable modems, and no other coax besides those 3 lines (counting the feed). I had already checked the 3 connections for corrosion and tightness when I was troubleshooting before. The splitter (Antronix CMC2002H-A 5-100Mhz 2 way) may be poor quality I don't really know, it's the only one I had on hand after finding the Extreme BDS108H the installer put in is no longer functioning about an hour ago. I'm waiting for an Extreme BDS102H to show up in the mail, already ordered, when it arrives I'll swap it out and check again. Can you tell me what the upstream power range should be? I think it might be worthwhile to swap out the coax between the modem and the splitter also. I don't see an RG value on it, it only says perfectflex series 6 18awg.
The Antronix is a very good quality splitter that Comcast uses widely, but it may be malfunctioning. Only a swap would rule that out.
That's RG6 which is the preferred cable. But it may not be *quad shield* which may be better depending on the length of the run. But it's also more difficult (stiffer) to work with.
40 to 50 dB is the preferred range with 45 being the *sweet spot*.
So if there is nothing that you can do to improve the connection quality, then you should get a tech out to investigate / correct the problem as stated.
Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.
Note: Not all modems will allow you to view the status page and some will have different URLs to access this info. If you are unable to access your modem’s status page, you can contact Comcast Customer Support and ask the support representative for these values.
@EG I removed the splitter and connected the cable modem directly to the drop from the pole, and get even more errors in the log. I don't want to waste your time, I'm escalating to Comcast, just wanted to get this additional info out there in case it changes your advice in any way
DBC-REQ Mismatch Between Calculated Value for P1.6hi Compared to CCAP Provided Value;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
Mon Jan 10 14:39:55 2022
(Critical (3))
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=[Edited: "Personal Information"];CMTS-MAC=[Edited: "Personal Information"];CM-QOS=1.1;CM-VER=3.1;
Downstream power is now out of spec, too high. Upstream power is lower, but still over 50
Cable Connection
Cancel Apply
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
@EG thanks for your help. Tech came out today and guessed the symptoms before I even had a chance to explain. He found and a filter, and removed it, but power was still out of spec. He escalated to another team who showed up an hour or 2 later. Power levels are in spec now based on the guideline you shared earlier. I now have uncorrectables, but I'm guessing that doesn't mean much by itself if we don't have other issues going forward?
Cable Connection
Cancel Apply
Frequency start Value
This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.
Accepted Solution
EG
Expert
•
91.7K Messages
13 d ago
Specs look great now. The uncorrectables may be due to the linework that was done. You can reboot the modem to reset the error counter and start from scratch. Keep an eye on the amount of them, and whether they happen quickly or over a longer length of time. The bottom line is if the connection is now more stable. Good luck !
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EG
Expert
•
91.7K Messages
18 d ago
The upstream power is WAY out of spec !!! That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.
In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, etc. Splitters should be swapped with known to be good / new ones to test.
Also check the coax cable for any damage such as cuts, nicks, kinks, sharp bends, etc.
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two-way splitter connected directly off of the drop from the street / pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.
Good luck with it !
(edited)
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EG
Expert
•
91.7K Messages
18 d ago
The Antronix is a very good quality splitter that Comcast uses widely, but it may be malfunctioning. Only a swap would rule that out.
That's RG6 which is the preferred cable. But it may not be *quad shield* which may be better depending on the length of the run. But it's also more difficult (stiffer) to work with.
40 to 50 dB is the preferred range with 45 being the *sweet spot*.
So if there is nothing that you can do to improve the connection quality, then you should get a tech out to investigate / correct the problem as stated.
Bear in mind that if the premises facing techs can not find or fix a problem at your home, it is they who are responsible for escalating it to their line / network / maintenance dept. techs. The problem may lie beyond your home in the local neighborhood infrastructure somewhere but it is their S.O.P. to start at the home.
Good luck !
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EG
Expert
•
91.7K Messages
18 d ago
BTW, the signal stat ranges / values are in the pinned Troubleshooting Tips topic at the top of this board's page: https://forums.xfinity.com/conversations/your-home-network/internet-troubleshooting-tips/602dae4ac5375f08cde52ea0
Check your signal levels
To view your modem’s status page go to http://192.168.100.1 or http://10.0.0.1
Note: Not all modems will allow you to view the status page and some will have different URLs to access this info. If you are unable to access your modem’s status page, you can contact Comcast Customer Support and ask the support representative for these values.
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user_f26f9d
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5 Messages
16 d ago
@EG I removed the splitter and connected the cable modem directly to the drop from the pole, and get even more errors in the log. I don't want to waste your time, I'm escalating to Comcast, just wanted to get this additional info out there in case it changes your advice in any way
Downstream power is now out of spec, too high. Upstream power is lower, but still over 50
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EG
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91.7K Messages
16 d ago
Yep. You need a tech out to properly balance the line. Good luck with it ! Please post back with how things turn out.
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