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story category Comcast: U-Verse Interfering With Our Network
Mixing and matching technologies can cause problems...
06:25PM Wednesday Apr 23 2008 by Karl Bode
tags: dsl · competition · business · hardware · cable · telco · install · trouble · networking
Tipped by Morac See Profile
Comcast and AT&T are engaged in a battle over in-home interference when both Comcast cable and AT&T U-Verse services are installed in the same premises. Comcast is claiming that "poorly-installed" U-Verse service is creating feedback for a number of customers in Illinois, potentially degrading service on entire nodes. Comcast claims that AT&T has not responded to their attempts to resolve the issue. Says Comcast of the problem:
"Comcast is disappointed in AT&T’s lack of responsiveness in addressing the damages they are causing our customers in the Chicago area," Comcast spokesperson Charlie Douglas told Ars. "AT&T has been aware of this problem for more than a year and yet they have been unresponsive and have no sense of urgency in addressing or fixing it. AT&T should act like a good corporate citizen and work with Comcast to resolve this privately."
Comcast is now seeking a not-so-private restraining order, while AT&T denies that U-Verse is the source of the problem.

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  4. Indie ISPs Eyeing Legal Action Against Bell Canada
  5. Tampa Tribune Highlights FiOS Billing Problems
  6. We Want Broadband -- Provided It's Aesthetically Pleasing
  7. Comcast Gets Investigated While Cox Gets Free Pass
  8. Comcast, Like AT&T, Takes Heat For Neighborhood Cabinets
Forums » Comcast: U-Verse Interfering With Our Network
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TK Junk Mail
Go ahead, make my day
Premium
join:2002-03-03
Margate City, NJ
clubs:
·Comcast


edit:
April 23rd, @06:31PM

Could be solved by 3rd party investigation

The judge should assign a master to investigate. He could then hire some 3rd party network expert(from some university unaffiliated or tainted by corporate sponsors). And the problem identification could then be based on facts and not on mutual accusations.
--
My BLOG .. .. Internet News .. .. My Web Page
bogey780

join:2004-03-19
Covington, LA

Re: Could be solved by 3rd party investigation

Comcast just needs a scapegoat for their service issues. There'd be no reason for backfeeding to Comcast nor would the interference be unidirectional.

compugeek
Have you pooped today?
Premium
join:2002-07-30
Pickerington, OH

Re: Could be solved by 3rd party investigation

It isn't a scapegoat, I have seen it first hand on an analyzer.

Geek
--
»www.itsnewtoyou.biz

justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
·AT&T Yahoo

Re: Could be solved by 3rd party investigation

So, is the interference being injected by installations where the HomePNA coax is accidentally left connected to the Comcast connection, or is it VDSL over POTS that's causing it?

Is it possible the enduser/customer is responsible for interconnecting the AT+T gateways that are using coax & Comcast coax networks?

Camelot One
Premium,MVM
join:2001-11-21
Austin, TX
clubs:
·VoicePulse

Re: Could be solved by 3rd party investigation

According to the article, the problem arises when the customer mixes UVerse with cable internet. In that instance, the cableco line would NOT be disconnected. Both signals are being injected into the same wiring, and it's not hard to imagine one causing issues for the other. It sounds like the UVerse techs should be installing some sort of backstop signal filter, which would stop the uverse signal from traveling back up the cableco line feed.
--
Intel Quad Core QX6700 @3500Mhz/Asus P5N32-E SLI/4x 1024Mb Corsair/Seagate 750.10/PNY 7800GTs SLI/Silverstone 850W/Custom water cooler

jt45

@comcast.net

and how do you know it is not causing problems. you dont know you just think you know. i agree with the first person . get a 3rd party in voled to look into this. you dont know that it is or is not causing a problem. you just like to think you know. stupid people!!!!!

a333
A hot cup of integrals please

join:2007-06-12
Corona, NY
·Verizon Online DSL


edit:
April 23rd, @07:49PM

Re: Could be solved by 3rd party investigation

Well, if AT&T equipment were to interfere with Comcast, it would be logically implied that the Comcast signals are interfering with AT&T's equipment, right?

Or am I missing something here..........?

And please register on the forums before you post. Being anon really doesn't give you much credibility.

Camelot One
Premium,MVM
join:2001-11-21
Austin, TX
clubs:
·VoicePulse

Re: Could be solved by 3rd party investigation

said by a333 See Profile :

Well, if AT&T equipment were to interfere with Comcast, it would be logically implied that the Comcast signals are interfering with AT&T's equipment, right?

Or am I missing something here..........?

And please register on the forums before you post. Being anon really doesn't give you much credibility.
I have to disagree that the interference would HAVE to effect both systems. You have to remember that the Comcast gear has been in place for years, while AT&T's gear was designed after the fact. It's quite likely the designers took into account that this problem might come up, and designed the UVerse gear to deal with it, or at the very least to ignore the interferring signal they knew might be an issue.

But yeah an anon from comcast.net defending comcast is a pretty tough sell.
--
Intel Quad Core QX6700 @3500Mhz/Asus P5N32-E SLI/4x 1024Mb Corsair/Seagate 750.10/PNY 7800GTs SLI/Silverstone 850W/Custom water cooler
espaeth
Misanthrope
Premium
join:2001-04-21
Minneapolis, MN
·Comcast
·Embarq


edit:
April 23rd, @08:32PM

said by a333 See Profile :

Well, if AT&T equipment were to interfere with Comcast, it would be logically implied that the Comcast signals are interfering with AT&T's equipment, right?

Or am I missing something here..........?
U-verse gear is one-directional on the coax side. It is DSL in, coax out. The impact on the U-verse side would be limited to the house that is hooked up wrong.

Comcast is 100% coax throughout the neighborhood.

If you connect a U-verse device to Comcast's cable plant you have the potential to affect everyone on that segment in the neighborhood.

I'm not sure why this would be limited to U-verse though; Verizon uses coax for FiOS as well, so one would have to imagine that this type of cross cabling has occurred on at least a handful of those installs as well.

Camelot One
Premium,MVM
join:2001-11-21
Austin, TX
clubs:
·VoicePulse

Re: Could be solved by 3rd party investigation

The difference, and the reason VZ probably hasn't had to deal with this, is that there is no reason to have Fios but use cable internet. Maybe a select few using cable as a backup, but not nearly the number of customers who want UVerse TV/phone with the faster speeds of cable for the internet connection.

So there you have it, AT&T could avoid the problem all together by offering faster speeds so that they have a better than cable product, which would allow the install techs to disconnect the incoming cable co feed
--
Intel Quad Core QX6700 @3500Mhz/Asus P5N32-E SLI/4x 1024Mb Corsair/Seagate 750.10/PNY 7800GTs SLI/Silverstone 850W/Custom water cooler

a333
A hot cup of integrals please

join:2007-06-12
Corona, NY

edit:
April 23rd, @09:11PM

Re: Could be solved by 3rd party investigation

nevermind, misspost

dnoyeB
Ferrous Phallus

join:2000-10-09
Southfield, MI

If your neighbor has FIOS, and left their coax connected it could interfere with your cable. Comcast is notorious for "disconnecting" its cable connection, yet not really disconnecting it and leaving it on for over a year before they actually get to the pole to remove it. I guess this means when someones cable is turned off, Comcast is going to have to send a tech right away to remove the connection. That will mean $$$ for comcast.
--
dnoyeB
"Then said I, Wisdom [is] better than strength: nevertheless the poor man's wisdom [is] despised, and his words are not heard. " Ecclesiastes 9:16

a333
A hot cup of integrals please

join:2007-06-12
Corona, NY
exactly, both FiOS and U-verse interface with coax in some way or the other. And one would think that Comcast would be quickest to lay blame to their biggest threat, which is Verizon FiOS, not U-Verse.
Peace,
a333
KingofCola

join:2007-02-07
Greer, SC
HPNA, VDSL2 and CATV operate at different frequencies, there is no overlap of services. U-verse is actually designed to allow CATV to run in conjunction with U-verse services. CATV and HPNA are separated by ~20MHz of spectrum.

en102
Canadian, eh?

join:2001-01-26
Valencia, CA
RF interference would be limited to a short distance on Uverse (i.e. the node is --
Canada = Hollywood North
cableguy619

join:2003-06-24
Chula Vista, CA

LOL OMFG... you serious? it is called if the customer chosies to keep both services the new service needs to run their own lines or a seperate line. if nto the only person affected will eb the customer in the end result. they need to be told up fron.. you need to make a choice or have another line rant o seperate the services...

RARPSL

join:1999-12-08
Suffern, NY

Re: Could be solved by 3rd party investigation

said by cableguy619 See Profile :

LOL OMFG... you serious? it is called if the customer chosies to keep both services the new service needs to run their own lines or a seperate line. if nto the only person affected will eb the customer in the end result. they need to be told up fron.. you need to make a choice or have another line rant o seperate the services...
I was going to point out the same thing. AT&T is trying to use the Comcast installed coax instead of running their own. They should treat the situation as a TOTALLY new install where there is no pre-existent coax and run their own RG6 Coax (that goes to the places where the TVs live).

Camelot One
Premium,MVM
join:2001-11-21
Austin, TX
clubs:
·VoicePulse

Re: Could be solved by 3rd party investigation

AT&T isn't using "comcast installed coax", they are using the in-home runs, which are owned by the owner of the property. With the exception of some of the more recent apartment/condo deals, the wiring IN the home is not run at the cost of the cable company. The builder puts it in. (or the owner adds it to an older home - still at the owner's cost)

So that end of the argument doesn't work. From a purely technical standpoint, Comcast should be taking the issue up with the customer who is choosing to connect both services to the same wiring. But it is the customer's wiring, atleast from the box in.
--
Intel Quad Core QX6700 @3500Mhz/Asus P5N32-E SLI/4x 1024Mb Corsair/Seagate 750.10/PNY 7800GTs SLI/Silverstone 850W/Custom water cooler
cooperaaaron

join:2004-04-10
Rockford, IL

Re: Could be solved by 3rd party investigation

That's only true if the owner had it installed. Where I installed ( Chicago suburbs, collar counties ) a high percentage of wiring was done by the cable companies, I'm talking 95 percent at the VERY least...
forefun

join:2004-04-21
Austin, TX

Re: Could be solved by 3rd party investigation

And once installed by the cable company, the inside wiring belongs to the customer. Normally, the cable company charges a customer to install wiring in their house. I know they charged me. Even if they didn't charge a dime, the wiring would still belong to the property owner.

factchecker

@cox.net

said by bogey780 See Profile :

Comcast just needs a scapegoat for their service issues.
And ATT needs a scapegoat, in this case, Comcasts supposed "service issues" for what is possibly a botched install.

After seeing telephone company AND cable company sabotage of each other's respective networks, I wouldn't be surprised if there is some hanky-panky going on in this situation...

How about the facts come out first, ehh ?

There'd be no reason for backfeeding to Comcast nor would the interference be unidirectional.
Actually, there are a couple of reasons to back feed into Comcasts network and none of them are innocent.

It more than like comes down to an installer goofing up.

As for the interference being unidirectional, the ATT customer probably is having issues, but because it would only affect ONE ATT customer, it would be harder to pin down as opposed to an entire node of Comcast customers.

The reality of the situation is that both companies are probably at fault - ATT probably goofed on the install and Comcast probably has poor ingress filtering on that node or segment.

packetscan
Premium
join:2004-10-19
Bridgeport, CT
clubs:
·Optimum Online

said by TK Junk Mail See Profile :

The judge should assign a master to investigate. He could then hire some 3rd party network expert(from some university unaffiliated or tainted by corporate sponsors). And the problem identification could then be based on facts and not on mutual accusations.
Another Baseless comment from our friendly lobbyist.
The point is AT&T is not advising or educating their customers when mixing services in the home which it should. In effect it's coming into the premise with blatant disregard for other carriers and their networks. Two unique signals coupled to the same line improperly and not separated will surely cause interference. If they can degrade service enough to the point that people will flock to them.
--
Reach out and Tap someone!

Jerm

join:2000-04-10
Richland, WA

I have no doubt this is actually happening...

It's the same kind of thing as if you were to hook a regular antenna directly up the CATV outlet - bad things happen.

I have no doubts stupid techs cross stuff all the time.

justbits
More fiber than ATT can handle
Premium
join:2003-01-08
Chicago, IL
·AT&T Midwest
·AT&T Yahoo

Re: I have no doubt this is actually happening...

My co-worker's neighbor had their Comcast box hooked up to their attic antenna, because the Comcast installer didn't bother to check if there was an attic antenna attached to the in-home coax. The installer should've known though since it was a new install. He could watch whatever they were watching by aiming his antenna at theirs and tuning in to channel 3.
Kearnstd
Elf Wizard

join:2002-01-22
Mullica Hill, NJ

Re: I have no doubt this is actually happening...

said by justbits See Profile :

My co-worker's neighbor had their Comcast box hooked up to their attic antenna, because the Comcast installer didn't bother to check if there was an attic antenna attached to the in-home coax. The installer should've known though since it was a new install. He could watch whatever they were watching by aiming his antenna at theirs and tuning in to channel 3.
that would be a cool thing to do if you had a C-Band dish and a ballgame was under blackout in your area. "accidently" hook the dish to an old antenna and let the neighbors catch the game.
--
[65 Arcanist]Filan(High Elf) Zone: Broadband Reports
cableguy619

join:2003-06-24
Chula Vista, CA

Bottom line

to lay it out in plain english.

Both Services work a majority of the same frequeny ranges and will affect one another in different areas depending on where they are carrying their services.

So a tech on either side can actually cause some kind of issue that will back feed into a providers system.
Answer Guy

join:2006-07-28
Grass Lake, MI
·Alltel Axess

Re: Bottom line

Yes, they both work in the same frequency and they do interfere with each other. However, the signal power level of the U-Verse is so much higher than the Comcast signal it easily over-powers it in the subscribers home. In fact, it could overpower the signal coming into the neighbors homes. Could it overpower the signal on the entire Comcast node, very doubtful.

Now, the real question is did AT&T do the bad installation, or did the homeowner do some modification without knowing the real impact. I've seen a lot of odd wiring jobs that some people do when they have no clue what they are doing.

factchecker

@cox.net

Re: Bottom line

said by Answer Guy See Profile :

Yes, they both work in the same frequency and they do interfere with each other. However, the signal power level of the U-Verse is so much higher than the Comcast signal it easily over-powers it in the subscribers home. In fact, it could overpower the signal coming into the neighbors homes. Could it overpower the signal on the entire Comcast node, very doubtful.
I think you already know this, but ATT's signal does not actually have to overpower the Comcast signal to create havoc. Even a weak ATT signal in the same frequencies could degrade picture quality, interfere with two-way communications and data services just by being present.
cableguy619

join:2003-06-24
Chula Vista, CA

Re: Bottom line

said by factchecker :

said by Answer Guy See Profile :

Yes, they both work in the same frequency and they do interfere with each other. However, the signal power level of the U-Verse is so much higher than the Comcast signal it easily over-powers it in the subscribers home. In fact, it could overpower the signal coming into the neighbors homes. Could it overpower the signal on the entire Comcast node, very doubtful.
I think you already know this, but ATT's signal does not actually have to overpower the Comcast signal to create havoc. Even a weak ATT signal in the same frequencies could degrade picture quality, interfere with two-way communications and data services just by being present.
CORRECT, noise at any level is not good...especially for the return path

Murphy

@rr.com
well said, i agree
koolkid1563
Premium,MVM
join:2005-11-06
Powell, WY
clubs:
·AT&T U-Verse


edit:
April 24th, @02:04AM

I don't know about which frequencies cable uses for which service(s), but I have an estimate on the ones U-verse uses. I know for sure that U-verse uses 8.5MHz for VDSL, as that is what their VDSL filter balun uses to get the VDSL frequency from twisted pair to coax is rated for. I don't know the exact frequency ranges of HPNAv3, but I do know HPNAv2 uses the 4-10MHz frequency band. I know that would probably affect a cable modem's upstream frequency if the cable company in that market is using a frequency in or near that range.

What baffles me is where would the Comcast demarc be introduced into the U-verse system? If VDSL and HPNA are involved on the same coax cable for U-verse, there is a diplexer in the mix. If the Comcast demarc is plugged into the VDSL leg along with the connection to the balun in the NID, it will only be subjected to the 8.5MHz VDSL signal. If it is plugged into the same leg as the RG would be (the combined leg), it would be subjected to both the VDSL and HPNA signals. If it is plugged into the HPNA leg along with the STBs, it would only be subjected to the HPNA frequencies.

Another thing one would have to find out is the strength of the signal at the output port of the device and the rate of signal dropoff for each foot traveled for each signal. Comcast's amplifiers *could* be amplifying these frequencies depending on which frequencies they use in the field. If not, would the distance from the affecting devices (RG/STB) be close enough to other subscribers to inflict any harm on their systems in these frequency ranges? You have to realize that HPNA was only designed as a home solution, not a network to span multiple residences or a whole neighborhood. VDSL on the other hand, since it is coming from the DSLAM, might be powerful enough to go further than HPNA, but which services would it affect? Again, I am not familiar with frequencies that cable companies use for their service, so I really do not know.

Edit: I did some looking and found out that one particular HPNAv3 to Ethernet bridge (model DPH548) has two different models that operate on two different bands. One operates on the 4-21MHz band and the other operates on the 12-28MHz band. It would only be logical for AT&T to be using the 12-28MHz band as to not interfere with the VDSL signal running at 8.5MHz when both are being carried on the same length of coax cable.

Samus82
Radly

join:2002-01-29
Chicago, IL
clubs:
·WOW Internet and C..

im a prem tech

We TAKE OFF comcasts drop and disconnect it from all of our wiring that we use. We dont use their splitters or anything. Most prem techs are trained very well to even cap off Comcasts lines with a terminator so it dosent just leak out.
--
Opinion is just a word people hide behind to try and justify them believing stupid things. It sure is easy to believe in something completely and totally stupid, say it's your "Opinion" and then everyone has to respect it.
JerryTimes

join:2002-01-09
Roseville, MI
·Cox HSI
·Comcast

Re: im a prem tech

You might take them off and use all new hookups, but the UVerse techs that don't are the problem. From what I've heard, when UVerse is connected in a home that previously had Comcast, and the tech uses existing lines (which happens in many cases) and the tech accidentally hooks the Comcast drop line up to the UVerse, it sends voltage and other frequencies up the drop into the system. (Not all drops are disconnected right away)

srtcb

@wavecable.com

Re: im a prem tech

This is exactly what happens. All outlets are activated, including the drop from the cable company. The ATT gateway uses the return path 20-40MHz to transmit data to the STB's over coax. This data is then transmitted onto the cable plant which is amplified back to the node. Most cable modems transmit in the 20-37 MHz range which overlaps with the U verse data. This will shut down the whole node RX path and disrupt all modems who share the same RX path. If multiple nodes are combined together, it will shut down all net or phone customers associated with the problem node. I have seen this numerous times. ATT offers a trial service around my area so the customer does not call for a disconnect from cable until they come to a decision what service to keep.
koolkid1563
Premium,MVM
join:2005-11-06
Powell, WY
clubs:
·AT&T U-Verse


edit:
April 25th, @12:44AM

Re: im a prem tech

HPNAv3 that AT&T is most likely using the 12-28MHz band. What nobody has been able to confirm is which side of the diplexer Comcast is getting tied in with assuming both VDSL and HPNA are using coax on these installs. Assuming the diplexer is installed at the Comcast demarc along with AT&T's demarc, it would be fairly difficult to get Comcast's demarc on the HPNA only leg or the combined leg without feeding Comcast's signal through the output of a splitter. In which case, the Comcast signal doesn't have much chance of reaching any device anyways that the customer might want to plug back in due to port to port isolation that most splitters do. Meaning that the HPNA would be going out to Comcast, but nothing coming in from Comcast. In which case, the Comcast HSI customer explained in Comcast's complaint wouldn't be able to get sync on their modem in theory regardless of frequency overlap.

Another thing that nobody can seem to confirm is just how strong of a signal the HPNA hosts and clients are putting out. My guess is nowhere near the output signal that cable modems are able to put out (~50-60dB I believe), seeing as HPNA devices are only designed to be a home network of sorts and aren't designed to be able to be heard all the way up the cable network. It would be another story if somehow Comcast's field amps are getting ahold of the 12-28MHz band and amplifying it, if it can still hear the HPNA devices signal at that point.

BK3

join:2001-04-10
Geneva, IL
·AT&T Yahoo

Good Corporate Citizen?

Comcast says:

.... AT&T should act like a good corporate citizen

Huh? AT&T a good citizen? The corp that would rather sue than negotiate in good faith? Like that's gonna happen.
--
April showers bring May flowers. Mayflowers bring pilgrims.

GlobalMind
Domino Dude, POWER Systems Guy
Premium
join:2001-10-29
Hollywood, FL

Comcast should talk

I love when one monolith PITA corporation tries to pull the moral high ground card with another monolith PITA corporation.

Comcast is about the last ones who should be calling out another company to be a "good corporate citizen."

In any event I can certainly see how this could happen if things aren't connected properly. Nevermind that it certainly seems that there aren't any measures in place to prevent the backfill of the Comcast network.
--
TheGlobalMind.com | Speed costs money. How fast do you want to go? | Trust the instinct to the end, though you can render no reason. Ralph Waldo Emerson

TimS

@sbcglobal.net

Why does Comcast not already have filters?

HomePNA the protocol used by AT&T to broadcast there network signals was designed to coexist with cable signals. There should be no interference. Why does Comcast not already have filters on there own equipment? People back feeding into the system has been an issue for years with security cameras and HTPCs.

Comcast only owns the coax on the out side of my house at least that’s what they told me when I needed a run inside my house repaired. I have every right then to use that coax for any services I wish.

In my area AT&T has the highest internet speed available at 10mbs. You can not get U-Voice IP phone without U-Verse internet.

tc1uscg

join:2005-03-09
Saint Clair Shores, MI
·Comcast
·WOW Internet and C..
·VoiceEclipse


edit:
April 24th, @12:40AM

AT&T, Ameritech, SBC.. still the same ole....

Having to deal with AT&T's HICAP and TSPOC's on many occassions, I can assure everyone this is their buisness model. It's never their fault for ANYTHING. They expect YOU to tell them what's wrong with THEIR network (and even help them figure out what's wrong on THEIR network) and if you can't, they blow you off a large majority of the time.
axus

join:2001-06-18
Washington, DC

ha

That AT&T vs. Comcast picture in the link is awesome.

Is the interference affecting internet, TV, or both? I can only see Comcast doing this if their TV service is affected. Or is it that AT&T is interfering with their TV monopoly?
DoubleK
Doublek

join:2003-03-04
Beloit, WI
clubs:
·AT&T Midwest
·Charter Pipeline

Wow all of you Anon posters, Booooo!

By any account how is it any companies responsibility to train technically inept customers.

The problem here really is both companies fault. They are always going to install with the path of cheap resistance.

ATT unhooking Cable and utilizing the homes rg6 is no different than the Cable company cutting the copper going to my NID installing their own NID and feeding said copper into it to take advantage of my homes existing phone line infrastructure.

They reap what they sow!

crispy
Premium
join:2002-01-12
Oxford, MS
·AT&T Southeast

Best idea

Comcast and AT&T fight each other to the death until there is nothing left of either of them. Then the best phone company (Verizon) and the best cable company (I don't know which) can come in and give the customers the service they actually deserve.

Mr Anon

@il.us

Hmmm...

You know this one is going to get a lot of replies and my own experience with U-Verse installers is that not all of them are top notch and I ended up redoing my wiring better than what I was left with. however some interesting things are going to be mulled over in my head when I think of this:

1. yeah there could be faulty install no doubt of that
2. There was a recent thread about "pirate signals over cable network" and the basic answer was no the tap or a notch would block your vcr's signal from reaching outside your house.
3. I would have to think that it would cause issues for booth systems

4. this doesn't matter but why would you get uverse without the internet? Max is pretty darn quick and I just prefer not to have to send out multiple payment but to each their own.

I agree have some thrid party look into it, each company has their share of bad installs, AT&T could just mandate that any install where the prior internet or TV service is to remain that they run new cat5 period. I don't understand though how this has been an issue for a year.

L J Monaghan

@sbcglobal.net

I don't believe it.

For the past year I have had both Uverse and Comcast internet service.

Never have I seen an instance of one interfering with the other in any way.

As far as I am concerned this is just another attempt by Comcast to attempt to safeguard their monopoly on TV service in certain markets.

Zeldas7777
Charter - Customer
Premium
join:2005-01-25
North Richland Hills, TX
·AT&T Southwest

Signal Issue

I would suggest removing one of the connections and trying each one out to check if their is a problem if not then this means that with both hooked up causing the problem.

Issue with backfeed interference

This is how the cable lines work:
1 you have a main trunk line
2 you have a line tap
3 you have drop from tap

the line tap does one thing taps into trunk line
which means anything that has the ability to transmit the same frequency onto the cable drop will also be transmitted to the trunk line then once on the trunk line it will then broadcast to and from line amps on the line for as long as the signal can go.

what happens when to different transmitters broadcasts the same frequency

well I went around with AT&T for a long time because I used to have 3 dsl lines in the same box. I finally got them to come out and run new drops total of 3. This separate drops with separate phone boxes on side of house fixed my disconnect issue. what does this mean well it means when you have two devices broadcasting on the same frequency using the same line their will no doubt be severe interference. Why is that you say well you start a signal fight on the line which ever is stronger will win or cause a lot of noise.

Gflash

@bellsouth.net

Re: Signal Issue

What ? -- Three adsl lines in the same box interfere with each other ? I have put several hundred in the same box and they never interfered . You must have forgot the Elves.

attphone guy

@rr.com

comcast

Wow well i think we should get rid of the power lines above the phone lines they interfere with the signal and cause a hum and static

Metrocastguy

@metrocast.net

Re: comcast

I work for metrocast cable In ct. We have been experiencing an issue we hadnt seen before and it has been discovered back to a customer that has uverse and cable here. I was searching around the net for similar problems when I came across here. Sorry for the anon posting as I will join. I am not blaming Uverse, I am just looking for a solution. Its a ever changing industry and things like this happen. I do forsee this only happening if the customer has both cable and uverse or perhaps they wernt properly disconnected from our service
scbastve

join:2008-07-05
Milwaukee, WI

Comcast: U-Verse Interfering With Our Network

I could not begin to count how many times I have found the cable co's VOIP service back feeding onto AT&T's network. Sometimes all the way to the switch in CO. Cause? Sub standard install, done by the cable co's tech not disconnecting at the NID. Although that is no excuse for the same quality work being done by AT&T techs, these things do happen. In my experience with U-Verse installs, the tech tries to wire the set top boxes with cat5 instead of coax. Picture quality is much better with cat5. Now I know that is not always possible, say in an apartment building. In those cases, the cat3 wiring that exists in the building is sufficient to feed the residential gateway, but sometimes you just have to use the existing coax, and busy techs at times forget to do things like, disconnect the cable co's drop. I would think that if this scenario were affecting a node, that the cable co techs have the testing equipment to trace and disconnect a drop that service has been terminated. I know I had to do it when VOIP started. And I don't recall reading about how the cable company was interfering with our network. Well not in a public forum anyway.
dcnblues

join:2002-09-19
Irving, TX

differing technologies

Not sure how this is happening, unless the techs are hooking up both systems using the same coax thru the home.

U-Verse comes in via DSL (mostly it's fiber up to the VRAD that's within 3000' of the premise.) But the TV signal isn't your usual analog or digital broadcast, it's all encrypted multicast IP data that only the u-Verse set-top can decrypt. The HPNA ports on the gateway turn the coax into network cabling, but it's still carrying IP.

NOW... if the installer hooks up the internal house coax to the coax OUTPUT of the set top... then that coax is now carrying the TV signal of whatever channel the customer is watching (same as with any set-top system, not just U-Verse.) That COULD be eavesdropped upon... but you'd not be able to tune your own set to other channels. It would only send the channel/app currently accessed on the box.

Probably what Comcast is upset about is techs not paying attention and cross-connecting the two networks by tapping the house coax to the back of the residential gateway device. This is what translates DSL to coax, and where the cable 'loop' would become another segment of the customer's LAN.

U-Verse pumps a LOT of IP traffic, most of it encrypted... but very little of it is broadcast. Most is unicast and multicast (client join) IP. To other clients? It'd be a busy network, but nothing they could tap into and watch. It would be interesting to tap into the RG and see how many new clients are requesting DHCP leases and such, though.
Forums » Comcast: U-Verse Interfering With Our Network


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