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Cable VoIP Sounds Better Than Some Landlines 153

Posted by Zonk from the kkhhh-can-you-hear-me-now dept.
A. G. Bell writes "A recent study that looked at the quality of phone calls came up with some surprising results. Ars Technica reports that while 'traditional' VoIP call quality lagged behind landlines, service from cable ISPs was much better because of their use of PacketCable: 'VoIP from the cable companies actually surpassed the traditional phone network in reliability, meaning that the service was more often available and connected calls without dropping them. Cable providers also led the way in audio quality; the top firm in Keynote's study actually turned in an MOS of 4.24, above most real phone networks.'"
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Cable VoIP Sounds Better Than Some Landlines More

Cable VoIP Sounds Better Than Some Landlines

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  • Surprising? No. (Score:1, Interesting)

    by 6031769 ( 829845 )
    Given the bandwidth of a cable (or any other broadband) connection I don't see why this should be surprising. Since a standard phone line needs to be upgraded for ADSL anyway, clearly the throughput with VoIP should be better than POTS.
    • Since a standard phone line needs to be upgraded for ADSL anyway, clearly the throughput with VoIP should be better than POTS.

      It's not all about throughput. Go ask any alarm system manufacturer. Most alarm companies won't touch VoIP with a ten foot pole, and with good reason.

      I just went through this myself; I have Optimum Voice (which drops calls about every five minutes, btw; I'm this close to calling Cablevision about this) and I just last week finally managed to figure out how to get an alarm system th

      • You basically either need to find a broadband panel (and they are not common) or you need to get an ABN adapter and use NextAlarm. But no alarm will work as it's designed to over a standard VoIP connection, for a variety of reasons.

        Sure they will. I just plugged the phone cord out of my ADT system into the phone port of my Vonage box and it worked. No additional hardware, no changes, no calls to ADT to change anything. I'm using Vonage over cable and as far as I'm concerned it works better than my land

      • Okay, why the heck are alarm system manufacturers routing alarm information through Voip, through the internet, instead of through the internet directly? That's just crazy.

        As far as reliability, I'd assume you that if the alarm system is very important to you, you would want redundant internet connections (a combination of cable, DSL, and CDMA service?). I'm sure you could at the very least get BETTER reliability than POTS.

      • Re: (Score:2)

        by hb253 ( 764272 )
        Just for balance...

        I've had Optimum Voice from Cablevision for just over a year. To date, I have not had a dropped call or bad quality call. In fact, call quality is pretty good - egual to, if not better than my former Verizon landline.

    • Re: (Score:3, Interesting)

      by ackthpt ( 218170 ) *

      Given the bandwidth of a cable (or any other broadband) connection I don't see why this should be surprising. Since a standard phone line needs to be upgraded for ADSL anyway, clearly the throughput with VoIP should be better than POTS.

      The analog bandwidth of a landline is sufficient for decent quality anyway. The most limiting factor is the poor microphone and speaker used in most of these. I've had some great phone calls over VoIP where I couldn't understand what the blazes the other party was saying

    • The problem isn't with bandwidth. Anytime you place a call on a land line (non-local), your signal on the analog POTS line is digited (8KHz, ADPCM, uLaw encoded) at the FXO (foreign exchange office) and transfered over a channel on a T1. 8KHz is plenty of bandwidth to transfer the human voice (Bell labs figured this out in the 50's)... With VOIP, extra bandwidth on one end doesn't give you a thing if you're calling a non-VOIP phone on the other end... eventually the signal gets transfered over a T1, at 8

  • Surprising? (Score:4, Informative)

    by RumGunner ( 457733 ) on Friday September 22, 2006 @12:58PM (#16162101) Homepage
    In my little hometown they still use the original ancient phone lines that leak signal like crazy. In fact, you could easily hear other conversations if you paused while talking on the phone. I'd guess that a majority of towns are using lines that are at least 30-50 years old still.

    • Re: (Score:2, Funny)

      by kfg ( 145172 ) *
      In fact, you could easily hear other conversations. . .

      Yeah, in my little home town of 30 years ago we had that problem too, we called it a "Party Line."

      KFG
    • It's been a few years since I've dealt with the cable modem industry much, but I find any claims of high reliability to be surprising.

      The economics of cable modems are that you're piggybacking service on top of Cable TV service, and the reliability numbers are driven by how many technicians with trucks they hire to go fix things when they break, plus how often installers break things by accident. For telephones, that's high reliability, with lots of techs and trucks, because there's not only a century of h

  • ...but how long until the major phone companies (Bell-South, AT&T, etc) start to QoS the packets from competing cable ISPs to lower the quality compared to traditional land lines?

    • Re: (Score:3, Insightful)

      by DragonPup ( 302885 )
      The idea behind PacketCable is that the call stays on the cable providers backbone for as long as possible, and only then does it go to the normal phone system. If any phone company tried to block or deblieratly degrade the service of phone service, I fully expect them to be on the recieving end of a lawsuit quickly.

      • Yes, but until any one cable company has coverage to every home in America, a call from NY to CA will most likly traverse another provider's network.
        As for the lawsuit, isn't that the whole debate about the net neutrality issue? What is different from SBC trying to extort more money from Google for data passing over its lines than AT&T trying to extort more money from Comcast or RoadRunner for the same reason?

        • Re:Encouraging... (Score:5, Informative)

          by DragonPup ( 302885 ) on Friday September 22, 2006 @01:17PM (#16162256)
          I should probably give the obligatory "I work for Comcast, but just as a dispatcher" warning, so I know a bit more about this than most people. :-)

          Yes, but until any one cable company has coverage to every home in America, a call from NY to CA will most likly traverse another provider's network

          Right, unless both sides have (for example) Comcast's VOIP, there will be a hand off between providers. But all phone companies pay when a call transfers to another provider's systems. The amount per call is next to nothing, but considering the number of phone calls made at any one time, it adds up to enough that I know Comcast has laid cable through areas they don't service just to carry their own VOIP calls. Same for cell phones(ever wonder why your phone always homes in on your provider's towers even if another one is closer?). So if Comcast hands off the last bit of a call to say AT&T's network, Comcast would pay AT&T as they would if the call went to Comcast's network.

          As for the lawsuit, isn't that the whole debate about the net neutrality issue? What is different from SBC trying to extort more money from Google for data passing over its lines than AT&T trying to extort more money from Comcast or RoadRunner for the same reason?

          Different issue. Over Comcast's packetcable thing, the data of the call only goes over Comcast's backbone(and no other part of the net), then it is handed off as a normal phone call.

          • Re: (Score:1)

            by MCZapf ( 218870 )
            What's so special about this, though? Don't ISPs try to keep traffic on their own networks for as long as possible anyway? Is it because Comcast is applying this technique to two different kinds of networks (IP vs. phone system)?

            • Re: (Score:2)

              by Joe5678 ( 135227 )
              I know nothing about cable networks, but I do know that ISP's don't try to keep traffic on their own networks for as long as possible. I didn't realize it had a specific name, but it's apparently called Hot-potato Routing [wikipedia.org]

              Think of it this way, if you have traffic that is destined for another network, would you dump it onto that network as soon as possible, or would you use up your own bandwidth and resources to get it as close as possible to the destination before dumping it to the other network?

              • Re: (Score:2)

                by pod ( 1103 )
                You would, if it is cheaper for you to maintain specific QoS on your traffic on you own network, rather than paying other carriers to respect your priority settings.

                • Re: (Score:2, Informative)

                  by pod ( 1103 )
                  And now that I took time to read the Wiki link, I see that is exactly what it says. So for commercial VoIP, you would specifically NOT use hot-potato routing.

          • Re: (Score:2)

            by kabocox ( 199019 )
            As for the lawsuit, isn't that the whole debate about the net neutrality issue? What is different from SBC trying to extort more money from Google for data passing over its lines than AT&T trying to extort more money from Comcast or RoadRunner for the same reason?

            Different issue. Over Comcast's packetcable thing, the data of the call only goes over Comcast's backbone(and no other part of the net), then it is handed off as a normal phone call.

            This comment just struck me as very, very dangerous. I'd hope
    • Wouldn't happen. Cable ISPs are mostly buying large pipes - the main question is whether they buy them big enough. The big problem is that the DSL access companies are very likely to *not* QoS the packets unless their customers pay extra, so VOIP will get swamped by your BitTorrent traffic, or music downloads, or similar high-volume data traffic. The cablecos also need to manage outbound traffic appropriately, but that's not too hard, even though they're almost certainly running 80kbps voice (64kbps raw
  • "Bhardwaj attributes the success of cable operators to their use of PacketCable, an IP multimedia transmission system optimized for cable plant. Providers who simply run standard VoIP connections over a cable modem do not see the same results."

    This seems to me like the ISP gets an advantage because of this PacketCable thing -- something I'm sure they will not be licensing to their VoIP competitors like Vonage. Not surprisingly, these 'other' VoIP providers fared worse then the ISP-provided VoIP service.

    • Re:Cable internet monopoly put to use... (Score:4, Informative)

      by DragonPup ( 302885 ) on Friday September 22, 2006 @01:09PM (#16162186)
      This seems to me like the ISP gets an advantage because of this PacketCable thing -- something I'm sure they will not be licensing to their VoIP competitors like Vonage. Not surprisingly, these 'other' VoIP providers fared worse then the ISP-provided VoIP service.

      That's the point. When a VOIP call is made from a cable ISP, the call stays on the cable ISP's backbone(but not the regular net. A wicked huge Intranet would be a better analogy) for as long as it can. Some cable providers created additional plant lines just for this. With Vonage and friends, they hop on the normal internet and do the 20 + jumps of fun. Think of PacketCable as an express lane for the Cable ISP's calls.

      • Re:Cable internet monopoly put to use... (Score:4, Informative)

        by N7DR ( 536428 ) on Friday September 22, 2006 @03:06PM (#16163102) Homepage
        That's the point. When a VOIP call is made from a cable ISP, the call stays on the cable ISP's backbone

        Before I comment, I'd better post my credentials to say what I'm about to say: I am a co-author on many of the PacketCable specs, wrote the standard text on the subject, and also run a little company that sells PacketCable security software.

        So, having said that, I would like to point out that your comment is accurate but may be a little misleading. It may indeed be true that today, and for most cable ISPs, the call stays on their network. But PacketCable was not specifically designed to be that narrow. Its architecture allows lots of things that cable companies have so far mostly not chosen to do. But, for example, there is no reason at all why the service has to be provide by a cable company. Sure, the cable company controls the pipe into the house (and the quality of service on that pipe), but there is nothing at all to prevent an ISP that decides that it doesn't want to get into the telephony business (and telephony could not remotely be described as easy) from contracting with a "real" telephony company so that that company provides service, with all the usual quality of service controls, over the ISP's network.

        To give a completely and obviously hypothetical example. Instead of deploying telephony itself, Comcast could have chosen to have Qwest run a Comcast-branded VoIP service over Comcast's network, including the last-mile access network. That service could be given exactly the same quality-of-service guarantees that Comcast has chose to give to itself, and presumably both Qwest and Comcast would receive a cut of each phone call.

        The corollary is that third-party providers (the Vonages of this world) do not have agreements and service-level contracts with Comcast. This means that their calls travel over the Comcast network using "best-effort" instead of some kind of guaranteed quality-of-service labelling. In particular, between the subscriber and the cable comapny, Vonage-like services travel over the ordinary standard primary DOCSIS flow from the cable modem, sharing it with all other traffic from that modem; PacketCable calls use special flows that have guaranteed latency-and-jitter limits specially designed for voice. Only the cable company can create and use those flows. (For the gory technical details, look at the DQoS [Dynamic Quality of Service] spec available at www.packetcable.com.)

        • Re: (Score:3, Interesting)

          by The Vulture ( 248871 )
          PacketCable calls use special flows that have guaranteed latency-and-jitter limits specially designed for voice. Only the cable company can create and use those flows.

          Precisely the point that everybody forgets. (I've done software development on DOCSIS cable modems and a CMTS - although I didn't do any PacketCable work, I've had to read some of the specs and have also configured test systems for use with it.)

          The cable company has a huge advantage over DSL when it comes to VoIP, because Vonage et al. share

          • Re: (Score:2)

            by JPriest ( 547211 )
            "and they don't necessarily work well together."



            The cable modem and VoIP eMTA's are integrated, take a look at the Motorola SBV5220 [motorola.com] for an example.

            • I was talking about the "Triple Play" solution, which consists of voice, data and video. I am not aware of a set-top box (which uses a QAM tuner for the video and a DOCSIS return channel) that supports PacketCable, therefore two boxes are required for the Triple Play. These two boxes don't necessarily work well in combination.

              The company that I work for is developing (and demoing) video solutions for the European market. One company that we are trying to sell to, their "Triple Play" solution consists of

    • Re: (Score:2)

      by prmths ( 325452 )
      Oh yeah, I just tried to get cable internet alone (without TV or voice), and they acted very rapidly to filter the analog TV out, cut my speed from 6 to 4, and jacked up the price to $60/month. Assholes.

      Ditto. Bastards. Thry eve force me to use THEIR POS modem....even though i have my own... i wish there was something better at a more reasonable price... ... i do not want DSL because i dont want to have to pay for a copper phone line. i use *only* the data connection from the cable co... no phone or TV...

  • depends a lot on the phone (Score:4, Interesting)

    by mytrip ( 940886 ) on Friday September 22, 2006 @01:04PM (#16162146) Homepage Journal
    I have a Cisco 7960 at home and a polycom 601 at work and they both toast landlines. We sell voip systems based on asterisk and a lot of it depends on whether the phone is full duplex, half duplex, if you use a switch or a hub, your isp. My isp is time warner and is very good. My same phone on my moms comcast would suck at 6pm when it is congested. VOIP on a pri definitely rules though if you have a full duplex phone. even on speakerphone.

  • some pure... (Score:4, Interesting)

    by Morphine007 ( 207082 ) on Friday September 22, 2006 @01:05PM (#16162159)

    ...anecdotal evidence for you:

    I'm using a Cogeco* VoIP phone, and it's awesome. It's clear as a bell, whereas the Bell POTS connection that I had previously had enough static on the line that it made it tremendously hard to hear the conversation. For the longest time I thought it was the handset...You can imagine my surprise when I switched over, used the same handset, and found that all that static had disappeared.

    * - I don't work for Cogeco and frankly couldn't care less if they survived or went belly-up tomorrow... but they're a cable company and it fits with TFA...

    • One reason you're paying so much for voice telco service is that they're supposed to fix things, and you can file a trouble ticket if they're broken, which yours obviously was. Back in the mid-80s, I was using 2400-baud modems from home (dialing in to the office), and the phone line I used for it started having trouble. The telco repair people really didn't understand the concept that "what's it sound like?" was "won't do 2400 baud, just 1200, even though it did 2400 just fine when the line was new". "No

  • Get with the times, AT&T (Score:3, Funny)

    by wbren ( 682133 ) on Friday September 22, 2006 @01:06PM (#16162161) Homepage
    A. G. Bell writes

    "A recent study that looked at the quality of phone calls came up with some surprising results. Ars Technica reports that while 'traditional' VoIP call quality lagged behind landlines, service from cable ISPs was much better because of their use of PacketCable: 'VoIP from the cable companies actually surpassed the traditional phone network in reliability, meaning that the service was more often available and connected calls without dropping them. Cable providers also led the way in audio quality; the top firm in Keynote's study actually turned in an MOS of 4.24, above most real phone networks.'"
    Even Alexander Graham Bell--back from the grave--is embracing VOIP. Come on AT&T, get with the times! Landlines are dead.
  • Typically, a well designed Digital Phone network will provide end to end QoS to protect calls from pops, clicks and whatever other impairments are associated with IP Data communications. Owning the network from the Customer to the PSTN Gateway (or even a completely protected IP Trunk) ensures full control over the call quality. Since the technology itself has a certain level of error survivability due to FEC in codecs, the call will not suffer from electrical interference typical with the worlds aging twi
  • :)

    I'm still going to keep my POTS line. It's my security blanket.
    • Except at work, I haven't really used a landline in years. Let alone depended on it. My mobile phone works fine for when I've really needed it.
      • Cell phones are OK but don't forget that on 9/11 the cell phones in NYC went down since their antennas we on the top of the WTC.
        • Actually, the Land lines went down to and so did the interet for most of NYC because many telco's and major ISPs had their equipment in a central office in one of basements of the WTCs.
    • The EMTAs(Cable modem+VOIP in one device) that Comcast use in New England have roughly 8 hours of built in battery life. ;)

    • Like the poster above: use a UPS for your network gear.

      I have Vonage at home, and all my networking gear, from the modem to the router to the adapter, is plugged in to a fairly hefty UPS.

      It's great to still have net access when the power goes out :)
      C

    • Re: (Score:3, Interesting)

      by AK Marc ( 707885 )
      I'm still going to keep my POTS line. It's my security blanket.

      Well, when my power goes out, I'm still on the Internet for hours. Perhaps if you were worried about calls when the power is out, you could spend $100 for a UPS. My cordless phones work great in a power outage. I bought one with a battery in the base. My Internet works great in a power outage. I have a UPS. The runtime is good too, as I have just the minimum data equipment plugged into the UPS and I have a laptop to work off of. I have

      • Well, when my power goes out, I'm still on the Internet for hours.

        How nice for you. So am I, but only because my internet is DSL. Almost every time there is a power failure at my house (in a small town, 2000 people) the cable goes out. I have to assume that that means that my phone service would be down as well.

        Fortunately, my landline phone has not failed since I moved into my house. In fact, I can recall only one time in my entire life that the phone service went out, but if I had a nickel for every t

  • true, in my experience (Score:5, Insightful)

    by bcrowell ( 177657 ) on Friday September 22, 2006 @01:11PM (#16162201) Homepage

    This matches my experience. We have Vonage via cable modem. Our neighbors who have POTS have had a number of lengthy service outages within the last yeur or two, whereas we've never had any. As far as audio quality, it just sounds normal to me.

    The only problems we've had have been with integration among the various parts of the system, and I guess that's not surprising, since it is multiple systems working together, rather than a monolithic system like Ma Bell used to be. The big problem we had was that every time someone would leave a voice mail on Vonage's system, our internet connection would die, and we'd have to power cycle to get it back up. The solution was simply to stop using Vonage's voice mail (which was klutzy anyway), and switch to using the answering machine that was already built into our phone anyway.

    A lot of people express concern about the 911 issue. Vonage now has automatic address recognition (if you set it up with them, which they try very aggressively to make sure you do), and from what I understand, there's no real data on reliability of Vonage's 911 versus reliability of POTS's 911. It's apparently quite common for POTS's automatic address recognition to fail, and for that reason, the first thing they always do when you call 911 is ask for your address anyway. The thing that does bother me a little about the 911 issue, regardless of the service provider, is that you can't test it without making a false 911 call. I don't like the idea of an important safety system that you can't test.

    • Re: (Score:3, Informative)

      by SoLoatWork ( 187259 )
      You can absolutely test 911 from any phone line. Simply call 911 and immediately mention to the operator you are making a test call to verify address information. Tell her what you think your address should be in their system and he/she can confirm this for you. As long as you make clear right off the bat you are on a test call, there is not a problem.

      • Re: (Score:3, Funny)

        by Chris Burke ( 6130 )
        That's a much better idea than what I do, which is to create the need for a real 911 call.

        "911 dispatcher? Hello? Yes, my address is 555 NotMyAddress, New York, MT. Is that what you have? It is? Great! That's what I wanted to know. Oh, the emergency? Of course there's an emergency, I wouldn't place a fake 911 call, ha ha! Yeah, I just stabbed a guy in the neck with a letter opener. on my front porch. That's right, some random guy, with a letter opener. Maybe he's a solicitor or something, is tha
    • The solution was simply to stop using Vonage's voice mail (which was klutzy anyway), and switch to using the answering machine that was already built into our phone anyway.

      Really? I still haven't been able to use a regular answer machine with Vonage yet. Any special tricks?

    • This matches my experience. We have Vonage via cable modem. Our neighbors who have POTS have had a number of lengthy service outages within the last yeur or two, whereas we've never had any. As far as audio quality, it just sounds normal to me.

      On the other hand, it doesn't match my experience. In the past fifteen years (The period of time I've had my own home and phone), the total downtime of my POTS can be measured in minutes (two digits at worst). In the last year alone my cable downtime can be measured

    • Re: (Score:2)

      by ugmoe ( 776194 )
      Vonage via cable modem usually is pretty good, but this isn't exactly what the article describes.

      The article is about a feature of the cable system called PacketCable which allows a cable modem to provide quality of service features to an embedded telephony device. The embedding of the telephony device in the cable modem allows the cable modem to know the telephone call details and communicate with the cable company headend to pre-request upstream bandwidth for the voice packets so they are not delayed

  • I have been using Comcast's Phone service for the past several months. Apart from the fact I incurred a phone number attached to someone with credit problems, the actual service of the phone is horrible. It sounds like I'm on a cell phone with a bad connection. Lots of static. On a few occasions, people have been unable to reach me (my phone never rang).

    Overall, I rate my Comcast experience as a 2 out of 10.
    • If you rate them at 2 out of 10, you are giving them credit. I have helped moved several ppl off of comcast voip. Comcast is one of the few companies that make Qwest look good (well, at times).
      • Yeah, probably too much credit.. although I consider anything below a 4 to be a failing grade in my book. If they were interested in customer service (which they're not), they'd try to figure out why their always rated so poorly. Of course, they make it noticeably more expensive to use their hi-speed internet if you drop their crappy phone service. It's basically a lose-lose scenario.

        Interestingly, Comcast's actual service makes TimeWarner look good (something that is incredibly hard to do), but ultimately,
        • Took them back to the regular phone (qwest), but left them on comcast internet (speed is ok). It is not what I prefer, but the problem is that comcast's network is now so crappy that you can not trust it. I have actually set up 6 ppl on asterisk. Interestingly, We found that Qwest's DSL connections do better than comcast. But I suspect that Qwest has the same ppl doing the customer service. When there is an outage, it sux. Funny thing is, that comcast used to be TCI/ATT and their network really had 24x7 up
  • I wonder if they were truely comparing "Cable VoIP" or the concept of providing dial-tone/phone service over cable. Things may have changed since I was working for a cable provider, but back in the day... Service would be provided by attaching a box to the side of the house. The service had an allocated set of "Channels". Just like channels are allocated in the normal cable spectrum that to deliver things like HBO and ESPN. The range used for TV never overlapped with Voice or Data. The range for Data
    • And from the article... "digital cable VoIP providers" refer only to the services offered by the cable companies, not to services like Vonage that simply plug into their networks" Which.. are not the same. Good job on comparing Apples to Oranges :)

    • Re: (Score:2)

      by shakah ( 78118 )
      Things may have changed since I was working for a cable provider...
      Yes, things have changed -- all recent deployments are IP-based, and even the older TDM-based ones (like the one you were exposed to, apparently) are switching to IP.

  • Not Surprising (Score:1, Redundant)

    by Dan Guisinger ( 15506 )
    Comcast drops their fiber so deep into neighborhoods around here its almost fiber to the home. On top of that, the cable around here is all burried so it avoids storm related outages, and lets not forget the biggest factor: voice is digital all the way to the home, the voice quality of course is going to be clear. There isn't a single run of analog signalling between the user and the cable company, thats why its so clear and such a predictable result.

    Nothing to see here :) Move along
  • They must not have checked my area. On average my cable line is down 2 days a month. Last month it was down for a week. The local cable company just responded "Sorry, we are working on it." (Time-Warner Cable) No ETA, No reason as to why it was down, No other information.

    Heck the last time my ISDN line went down was 3 years ago. VOIP is nice but with the issues that my local cable has keeping the system up and running, Ill wait.
  • I am using shaw for phone in canada over Cable, and I have to say it is way more convienent that the same offering from Telus. The value that shaw offers is unsurpassed in that it includes unlimited long distance in North America within the monthly fee. My monthly bill for this service is around $50 CAD each month. I am from the US so, my long distance bills with Telus used to be quite high, even using call arounds and different calling plans. I am officially a believer. Sound quality is great. Never
  • Here in India I use Vonage's VoIP @ the lowest bit rate setting of 32 kbps (on a 256kbps internet)& still the voice quality is better than ordinary landline.(& its up 24x7)

    Add to that there is no 1 sec timelag-delay in conversations through VoIP on calls to US .

  • Vonage over Comcast HSI (Score:1, Interesting)

    by Anonymous Coward
    This is a real bitter subject for me. I (try to) use Vonage over Comcast's internet service, but I get daily service outages, dropped calls and overall poor sound quality. I do not blame Vonage for any of these problem. Whenever I call Comcrap to complain about their internet service they always ask what I use the internet for: surfing, e-mail, etc. When I reply with Vonage, they always try to sell me their VoIP and I always say, "it doesn't matter what VoIP provider I use, it's still your internet conn
    • The "cable phone service" in question is NOT VoIP. It is a TDM service over the DOCSIS digital cable standard.

      This gives you an uncompressed DS0 digital phone connection, with no dropped packets, and with signal quality equivalent to having a few feet, rather than miles, of wire between the POTS instrument and the "phone company"'s D-A converter.

      VoIP uses lossy compression, introduces much more latency, has dropped packets due to internet congestion, and has rotten timing for the A-D/D-A conversions.

      You wo

      • Re: (Score:3, Informative)

        by nxtw ( 866177 )
        VoIP uses lossy compression, introduces much more latency, has dropped packets due to internet congestion, and has rotten timing for the A-D/D-A conversions.


        VoIP uses whatever codec it's configured to use, which could be great-sounding G.711 alaw/ulaw (as used on the real phone system) or GSM (not so good).
        • Using bare G.711 will improve the quality. But it won't do a thing about packet drop, packet jitter, or clock inaccuracies.

          To see the effect of clocking inaccuracies, try this: Configure your VoIP for G.711 and try to make a 56k modem connection over it and see what speed you get.

          Or try to send a FAX, ditto.

          • Re: (Score:2)

            by nxtw ( 866177 )
            Jitter still causes issues, but at my office we've done what's possible to minimize it. T.38 and a real phone line resolve faxing issues... and we've got no need for 56k.

            We've got RoadRunner business class cable, which is nice and fast, but at least 40ms to anywhere & with very jittery routes. Receiving faxes worked about half the time and sending was much less.

            The solution was to get AT&T DSL and use it primarily for VoIP. Destinations like Google and Akamai mirrors are 17ms away and our key VoI
          • The clocking inaccuracies can actually be deliberate, to reduce the number of pops and clicks on the line when things do go to shit. I have used faxes successfully between Asterisk servers running older (1.0.x) versions of Asterisk (and over a VERY clean, heavily QoS'ed network link), but with the newer jitter buffer in 1.2 which is much more stable for voice it's damn near impossible to run faxes with the stock code. Even a 2ms change in latency (smaller than the time needed to transmit a single 1500 byte
  • The power goes out? No power to the modem, no VoIP. Or how about when the tech puts a trap on your phone because he thinks you're pirating cable? (Happened about 5 times to a friend of mine with business class cable internet). Or how well does it work when the cable company screws up, and burns out a bunch of modems with a too strong signal (happened to many people around here). Or what happens when the weather gets exceptionally hot, or exceptionally cold and wreaks havoc with the S/N ratio of the lin
    • VoIP sounds better than my landline because my local loop is so long that the engineer determining if I can get DSL or not was astonished I was even capable of getting voice.
    • We are going to be installing eMTAs that have a 16 Hour battery backup for power outtages. Cable companies also backup their plant equipment with stand-by power supplies. The other point is that the trend in recent years is for people to make use of cordless phones more often than not. When the power is out, a cordless phone doesn't work regardless of who is carrying the call, unless of course you have alternate power for your phone, then see my first two points.

      All this said, I don't know what your cabl
  • Cable providers also led the way in audio quality

    What we all REALLY want to know is how well does it handle our Dial-Up connections?

    • Re: (Score:2)

      by shakah ( 78118 )
      though I'm assuming you're going for a "funny" moderation, I'll bite...

      What we all REALLY want to know is how well does it handle our Dial-Up connections?
      Apparently well enough. We monitor a few PacketCable deployments and see quite a bit of dial-up to RoadRunner and the like -- you gotta love the digital-to-analog-to-digital-to-analog-to-digital approach to Intenet connectivity.

  • Agreed - very good service (Score:3, Interesting)

    by us7892 ( 655683 ) on Friday September 22, 2006 @01:30PM (#16162363) Homepage
    I just got VoIP two months ago through my "local" cable company, and the voice quality has been excellent. And, the bill was even better! So far, so good.

    An interesting side not if you're a Verizon phone and DSL customer. Simply mention the fact that you're dropping DSL for cable and they first try and scare you by saying you are on a shared network and will certainly be targeted by intruders. If you can put up with their speach, then they'll offer at least one free month, and in my case, $10 less per month to stay with their DSL.

    Then, finally, the second call to cancel phone service they give a speech about unreliable 911 service and dropped calls with VoIP. If you can patiently wait for that speech to conclude, they'll offer another discount to keep you as a land-line customer. In my case, it was $10 again! No rebates on long-distance though...

    Bottom line, call up your phone company now, and say you want to cancel DSL and/or land-line service. You will certainly get a free month and a monthly discount.

    • Re: (Score:3, Interesting)

      by NMerriam ( 15122 )
      Indeed, this works both ways. There was a local SBC promotion with Yahoo! for DSL at $19.99/month, and if you had cable you could call up and go through the motions to cancel, tell them you were leaving for that deal, and they'd match it. Pretty big discount considering they charged $45/month for Cable internet for those of us who don't have Cable TV as well.

      Of course, I live in an old building with horrible wiring and could never get DSL, so it was all a bluff.
  • I lived in 3 different towns in NJ and one in CA and I think the landline has gone down like once in 25+ years. I've never had a landline to landline call dropped, ever. I didn't even think that was possible.

    I have had the cable drop off dozens of times though as have most people I know. I'd rely on Verizon for VOIP in a second but I would trust Cablevision to deliver my email. If what they are saying is actually true on a national scale then I'm shocked.

    • Re:I guess it depends where you do the study (Score:4, Interesting)

      by king-manic ( 409855 ) on Friday September 22, 2006 @01:57PM (#16162568)
      I lived in 3 different towns in NJ and one in CA and I think the landline has gone down like once in 25+ years. I've never had a landline to landline call dropped, ever. I didn't even think that was possible.

      I have had the cable drop off dozens of times though as have most people I know. I'd rely on Verizon for VOIP in a second but I would trust Cablevision to deliver my email. If what they are saying is actually true on a national scale then I'm shocked.

      Landlines in most areas are regulated. If their dropped calls/ 1000 rise above a certain level they get fines. Most areas are about 9-15 / 1000 before fines come into play. POTS are rarely fined.

  • If I remember DOCSYS correctly ... (Score:4, Informative)

    by Ungrounded Lightning ( 62228 ) on Friday September 22, 2006 @01:36PM (#16162406) Journal
    Cable providers also led the way in audio quality; the top firm in Keynote's study actually turned in an MOS of 4.24, above most real phone networks.

    If I recall the DOCSYS standard correctly (that's the one for cable settop boxes), the framing provides the phone company TDM-style 8 kHz synchronized clock, and the phone signals are carried as full-rate uncompressed bytes.

    In other words, POTS-over-cable is a 64 kbps synchronized digital signal, identical to what's carried on the phone companies' own ISDN, T, and SONET carriers, and is switched onmodified on and off the rest of the digital network unmodified. The A-D conversion happens in the settop box. It's like having your POTS phone at the switching center within wire-feet of the multiplexer. (The clocking is also good enough to encode analog signals from FAX and 56K computer modems. It has to be, as a side-effect of the need to time the upstream packets properly.)

    POTS, on the other hand, is A-D converted at a central office or a "remote terminal" (in a box at the curb) and carried the rest of the way - blocks to miles - in one of a bundle of wires. This is subject to crosstalk, distortion (selective delay and attenuation of higher frequencies), and a number of other pathologies that lower the signal quality.

    So it is not at ALL surprising that cable POTS signal quality beats telco POTS. Cable's signal is about as pristine as you can get.

    (And VoIP isn't in the same ballpark, due to both compression and timing uncertainties.)

    • (Which goes to show how long ago I was looking into it. B-) )

    • Re:If I remember DOCSYS correctly ... (Score:5, Informative)

      by redphive ( 175243 ) on Friday September 22, 2006 @02:07PM (#16162633) Homepage
      Just a matter of clarification on some of your points:
      DOCSIS is an ackronym for Data Over Cable Service Interface Specification, this has nothing specifically to do with voice or set-top boxes. There are two standards that deal with those
      PacketCable is the cablelabs standard for voice.
      OpenCable is the cablelabs standard for settop boxes.

      There is no synchronized clock with regards to DOCSIS. PacketCable uses VoIP technology and, as the name implies, uses ip data packets for call transmission.
      • There is no synchronized clock with regards to DOCSIS. PacketCable uses VoIP technology and, as the name implies, uses ip data packets for call transmission.

        There is a synchronized clock with DOCSIS.

        Note that all three of the supported data rates are even multiples of 8000 hz. This is not a coincidence - it's where the clock is carried.

        Now look at, say, Annex A of the 3.0 spec ("Timing Requirements for Supporting Business Services over DOCSIS"):

        A.1 CMTS

        DOCSIS 3.0 CMTSs have the following timing and synchro

        • I don't have the voice transport standard itself handy. But if you go to the OpenCable portion of their web site ...

          Meant PacketCable (the relevant standard).
    • If you're seeing a MOS above 4, it's either doing a 64kbps telco-style G.711 Voice codec, which is about 80kbps after you add IP overhead (takes a big chunk of a 128kbps upstream, if you still have that), or else it's PC-to-PC calls doing a codec that takes advantage of the higher analog bandwidth you can get using a PC soundcard (e.g. 5.5, 8, or 11 kHz audio signal instead of 4kHz for telco (the clock rate's twice the bandwidth), and probably 16-bit A/D samples instead of 12-bit A/D companded down to 8-bit
  • Something to consider:

    1. How does keynote benefit?
    Keynote's VoIP Competitive Monitoring Solution addresses the need of marketing and operations executives to understand their performance relative to competitors, and to gauge the impact on the end-user experience of both their infrastructure investments in new markets and their enhancements to services in existing markets.

    They have a pretty big incentive to excite some potential customers.

    2. What was the methodology?
    Keynote placed local and long distance Vo

  • Cheaper than VOIP (Score:3, Insightful)

    by Apocalypse111 ( 597674 ) on Friday September 22, 2006 @01:52PM (#16162521) Journal
    Teamspeak, Ventrillo
    Granted, this isn't really a phone replacement, but if all the people I want to talk to are on their computers anyways, then it works great.
  • If there is one thiing I dislike about VoIP calls it is the lag time. It seems that when I am on a conference call, it is hard to jump into a conversation because when you wait for the right time to jump in and start talking, someone else also decided to talk at the exact same time, but you only learn about it a bit later and talk over whoever else jumped ahead of you. It really makes you look like an asshole.

    VoIP service: Cox Cable
  • ... it'll be more available than a land-line. Since my cable modem seems to have a 10% chance of dropping for an hour or two exactly at midnight on any given weeknight, and a 20% chance on any given weekend night, that sounds like it would be *very* reliable. ComCrap seems to have picked midnight as the time to perform any maintenance they want, without informing their customers.

    steve
  • I love vonage save for one glitch. I must say "Hello" twice as the first one is never heard by the calling party.

    Does this happen to anyone else?

    Cheers,

    Bill

  • I use Asterisk with pots, and voip at work on a dsl connection and at home on cable, and it works nicely. Thats the good part.

    At home, I watch the commercials for Charter voip, and just roll over laughing. While my sytems at home and work are all on UPS systems, and will hold for at least 6 hours, Charter doesnt. If the power is out, so is the cable.

    Every time it rains a quarter of in inch, the cable goes down, this is even after they have came out and fixed lines, replace amps etc.

    Until the cable company c

  • My VoIP bill so far has been about $5 for 16 months of service - after I dropped the scumbags at Vonage with their $10 disconnection fee.

    So in May 2005, I pre-paid $10 for a teliax [teliax.com] account that I use for the type of calls that would eat into my included cell airtime - calls to 800 customer service numbers which involve long wait times. I still have about $5 left, even though I've made quite a few calls.

    I also make many long international calls using voiptalk [voiptalk.org]. Excellent sound quality, barely appreciable

  • Worked great on Skype (Score:2, Informative)

    by gatesvp ( 957062 )
    The first time I connected on Skype (from Shaw in Manitoba to Telus in Alberta), the voice quality was amazing. My father instantly noted that I sounded like I was "right there". Just like watching HD for the first time, other phones (especially mobiles) sound so much worse since we've started runing Skype.

  • So the real story here is... (Score:3, Interesting)

    by NoMaster ( 142776 ) on Friday September 22, 2006 @05:11PM (#16163781) Homepage Journal
    ... "VoIP with bandwidth to spare, controlled low latency, and QoS is sometimes almost as good as a dedicated voice network"?

    Gee, any telco engineer or high-level tech could have told you that...

    Disclaimer: I've been one. From a purely technical POV, VoIP is something of a con. It's attractive to end-users because it offers a chance to break free from the telcos. It's attractive to telcos because it allows them to homogenise their networks onto a single IP-based platform. Technically, though, it's a shitload of kludges to shoehorn something into a transmission platform that was never designed for the requirements of that kind of traffic. Underneath those kludges it's unreliable, inconsistent, and doesn't scale terribly well - though, because it's based on commodity technology, it's relatively cheap to implement/expand.

    • From a purely technical POV, VoIP is something of a con. It's attractive to end-users because it offers a chance to break free from the telcos.

      From a purely technical POV, breaking free of the telcos is the best thing that could ever happen to voice comms. They are primarily responsible for holding the field back decades in order to preserve their monopoly business model.

      The big advantage of VoIP, as far as I'm concerned, is flexibility on local networks. Trunk transfer is nowhere near as interesting compar

  • Not Mediacom at least. I don't think that I have EVER had my phone go out due to the phone company's problem. One time I couldn't use my phone because we had a storm and it fried a modem, but when I disconnected my modem the phone worked. However my cable internet has been a nightmare in two different places that I have lived. The two other people I know that have cable internet have also had it go down regularly. The only way that I could see PacketCable being more reliable is if it uses a total diffe
  • Not surprising with any broadband VoIP. People remarked from day one that my quality with Skype on mediocre DSL was superior to my landline desk phone.

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