http://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/ Engadget HD Comments for ADSL2+ isn't up to the HD challenge http://www.engadgethd.com/media/feedlogo.gif http://www.engadgethd.com en-us Copyright 2009 Weblogs, Inc. The contents of this feed are available for non-commercial use only. Blogsmith http://www.blogsmith.com/http://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/http://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/
This illustrates how you report on what you do not know. Every physical telephone line in America is UTP, or Unshielded Twisted Pair. Coax is a single, shielded conductor.

Now, you could have known this had you spent the 30-seconds it takes to rip open a telephone line next to your desk, kitchen counter, etc., etc., etc.

Also, you might try to expand on your research before you report blindly. ADSL2+ is only one of several xDSL technologies one or more of the American telephone companies are considering. You mention nothing of VDSL or VDSL2, which presents even more bandwidth.

And had you spent a day or two on a website like DSL Reports maybe you could learn a thing or two about the xDSL technology being deployed these days, which so happend to bring the DSLAM (DSL multiplexer) a lot closer to the customer's neighborhoods and it connects them to a telephone companies core network using Gigabit Ethernet over fiber optic cable.

And you even prove the inability to even bgin debating the platforms of deployment by not even mentioning what the real potential limitations are and how they relate to HD in the first place. Do you even know?]]>Sep 16th 2006 5:17PMhttp://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/http://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/
1. ADSL2+ is stated to offer between 12-15 Mbps per twisted pair of telephone lines, which of course is dependent upon your distance between the DSL mux (DSLAM) and the STB. If the plan were to use a single pair of twisted cables (a la phone service) then transmitting 8-9 Mbps of MPEG-4 HD content would not afford much more bandwidth for, say, a second HD channel to be received simultaneously.

2. Every telephone company (ahem, ILEC) in the USA consider deploying IPTV over twisted pair is approaching it using either ADSL2+ via bonded pair (set of two pair) to provide 20-25 Mbps bandwidth, VDSL to provide 35-60 Mbps, or VDSL2 for up to 100 Mbps.

3. IPTV can stream video using a variety of video codecs including the conventional MPEG-2, the more aggressive MPEG-4, and even VC1 and WMVHD. Current off the air broadcast 1080i is about 19.2Mbps using MPEG-2, and can be delivered with 8-9 using MPEG-4 or VC1.

4. Because of a need to deliver voice, Internet, and multiple streams of video are planned for, the projects will be to afford multiple SD and HD STBs simultaneously. The only telephone company consider ADSL2+ is BellSouth, and considering that they are merging with AT&T (ahem, SBC), and that AT&T plans on using VDSL initially and VDSL2 later, I would think the minimum bandwidth is sufficient for their target customer.

5. Unlike traditional broadband via the telephone companies, the common loop-lengths (distance between your home and the telco equipment) will no longer be 18,000-21,000 feet, but around 5,000 or less. This need is a result to insure a lot more bandwidth than what is currently available via Internet-only services.

6. In order to reduce the loop lengths the telephone companies must move their equipment closer to the customer. The modern method for doing this is to use fiber from the DSL mux to their core network and do so via Gigabit Ethernet.

7. Unlike traditional CATV and satellite transmission, the telephone company is using the approach of IPTV to selective send to your home only the channels you are watching or recording off of. CATV and DBS (satellite) sends to you every freaking channel (waste of bandwidth for CATV). This is why CATV are starting to warm up to using IPTV and reducing the local loop bandwidth consumption.

I could go on, but remember that website I suggested?]]>Sep 16th 2006 5:33PMhttp://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/http://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/
Coax still has LOTS of life left in it though. The current DOCSIS technology can take us up to around 38mbps down and 10mbps up, but that's assuming the cable co's don't roll out DOCSIS 2 before then, which I am sure most will. DOCSIS 2 has a limit upwards of 40mbps down, and 30mbps up. While it will be a ways yet, DOCSIS 3 is 160mbps down and 120mbps up.

All that speed in our current COAX infrastructure. Yes, the cable co's will certainly have to do some massic upgrading just like the telco's to their headends BUT there's no complete infrastructure re-do like a lot of telco's are doing now with all the fiber upgrades to everyone's house.]]>Sep 16th 2006 5:54PMhttp://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/http://www.engadgethd.com/2006/09/16/adsl2-isnt-up-to-the-hd-challenge/
I never pretend to know much about DSL or any of it's variations.

I can't even believe you would argue that twisted pair vs Coax. I have never heard that coax has less throughput than even twisted pair for long distances.

QAM 256 is capable of 38Mbps per 6 mhz channel. In my area they are on a 900Mhz system. That is 5.7Gbps, twisted pair that can do that is VERY expensive and limited to 100 Meters. If the existing phone network was that great then Telcos wouldn't be spending all that money to roll out fiber to the premise. ]]>Sep 16th 2006 6:30PM