6 ms·

"In contrast, XG-FAST uses an increased frequency range up to 500 MHz to achieve higher speeds but over shorter distances. Bell Labs achieved 1 Gbps symmetrical

"In contrast, XG-FAST uses an increased frequency range up to 500 MHz to achieve higher speeds but over shorter distances. Bell Labs achieved 1 Gbps symmetrical over 70 meters on a single copper pair. 10 Gbps was achieved over a distance of 30 meters by using two pairs of lines (a technique known as “bonding”). Both tests used standard copper cable provided by a European operator." 30 meters with bonded pair for 10 Gbps. While this is pretty cool, due to distance limitation we are not getting telephone line modems that can outstrip fiber optics.

te_platt 12y ago
Not to mention the fact that telephone lines are bandlimited at about 3000 Hz.
- wmf 12y ago
  That only applies to voice calls, not DSL.
  - quink 12y ago
    It does apply if you've got a pair gain system sitting in the middle, but you're essentially right.
  - te_platt 12y ago
    It applies to any call outside of the local loop. From the dsl wikipedia entry: Because DSL operates above the 3.4 kHz voice limit, it cannot pass through a load coil. Load coils are, in essence, filters that block out any non-voice frequency. They are commonly set at regular intervals in lines placed only for POTS service. A DSL signal cannot pass through a properly installed and working load coil, while voice service cannot be maintained past a certain distance without such coils. Therefore, some areas that are within range for DSL service are disqualified from eligibility because of load coil placement. Because of this, phone companies endeavor to remove load coils on copper loops that can operate without them, and by conditioning other lines to avoid them through the use of fiber to the neighborhood or node
nardi 12y ago
> While this is pretty cool, due to distance limitation we are not getting telephone line modems that can outstrip fiber optics. From the article: "XG-FAST can help operators accelerate FTTH deployments, taking fiber very close to customers without the major expense and delays associated with entering every home." So you actually are getting a modem, hooked up to your telephone line, that goes up to 70m over telephone cable to the street, and then fiber the rest of the way. Makes a lot more sense than literally doing fiber to every home.
- sjtrny 12y ago
  Hardly. You are forgetting that most people's copper cabling is degrading quite rapidly or is already of very poor quality. Furthermore the number of nodes required on the street due to the 70m limitation would be a lot higher than with FTTP.
  - XorNot 12y ago
    Exactly - this changes nothing. You'd still be paying workcrews to go street-to-street digging things up and running things through conduit. At the point you're doing that, the marginal cost of getting them there is much higher then the cost of the equipment or cabling they'd be installing.
    - Turing_Machine 12y ago
      Running cable on poles or pulling it through conduit is much, much, much cheaper than fiddling around in someone's attic or crawlspace. The appointment has to be scheduled (i.e., the homeowner has to be there), you have to worry about the three hundred pounds of boxes they've got stored in the way, the crawl space or attic may be brutally hot or cold, have wasps, raw sewage, mud, or any number of other hazards. It's a slow and expensive job.
      - sliverstorm 12y ago
        Not to mention legal hooplah and potential billing. Digging up the streets requires permission from the city, and maybe you send them a bill for some of your services. Digging up people's front lawns requires permission from every homeowner, and if you are offloading cost you have to bill each homeowner...
jpmattia 12y ago
> While this is pretty cool, due to distance limitation we are not getting telephone line modems that can outstrip fiber optics. I doubt anyone is under any illusions that the copper is going to outstrip fiber. However, it is still an important result: There are many places that are stuck with old-fashioned twisted pair and it takes literally an act of gov't to lay down fiber. Rather than leaving that population out in the cold, this result gives hope that they may have cutting edge connectivity. The real issue is commercializability, which has not been Bell's traditional strength.

te_platt 12y ago

Not to mention the fact that telephone lines are bandlimited at about 3000 Hz.

wmf 12y ago
That only applies to voice calls, not DSL.
- quink 12y ago
  It does apply if you've got a pair gain system sitting in the middle, but you're essentially right.
- te_platt 12y ago
  It applies to any call outside of the local loop. From the dsl wikipedia entry: Because DSL operates above the 3.4 kHz voice limit, it cannot pass through a load coil. Load coils are, in essence, filters that block out any non-voice frequency. They are commonly set at regular intervals in lines placed only for POTS service. A DSL signal cannot pass through a properly installed and working load coil, while voice service cannot be maintained past a certain distance without such coils. Therefore, some areas that are within range for DSL service are disqualified from eligibility because of load coil placement. Because of this, phone companies endeavor to remove load coils on copper loops that can operate without them, and by conditioning other lines to avoid them through the use of fiber to the neighborhood or node

nardi 12y ago

> While this is pretty cool, due to distance limitation we are not getting telephone line modems that can outstrip fiber optics. From the article: "XG-FAST can help operators accelerate FTTH deployments, taking fiber very close to customers without the major expense and delays associated with entering every home." So you actually are getting a modem, hooked up to your telephone line, that goes up to 70m over telephone cable to the street, and then fiber the rest of the way. Makes a lot more sense than literally doing fiber to every home.

sjtrny 12y ago
Hardly. You are forgetting that most people's copper cabling is degrading quite rapidly or is already of very poor quality. Furthermore the number of nodes required on the street due to the 70m limitation would be a lot higher than with FTTP.
- XorNot 12y ago
  Exactly - this changes nothing. You'd still be paying workcrews to go street-to-street digging things up and running things through conduit. At the point you're doing that, the marginal cost of getting them there is much higher then the cost of the equipment or cabling they'd be installing.
  - Turing_Machine 12y ago
    Running cable on poles or pulling it through conduit is much, much, much cheaper than fiddling around in someone's attic or crawlspace. The appointment has to be scheduled (i.e., the homeowner has to be there), you have to worry about the three hundred pounds of boxes they've got stored in the way, the crawl space or attic may be brutally hot or cold, have wasps, raw sewage, mud, or any number of other hazards. It's a slow and expensive job.
    - sliverstorm 12y ago
      Not to mention legal hooplah and potential billing. Digging up the streets requires permission from the city, and maybe you send them a bill for some of your services. Digging up people's front lawns requires permission from every homeowner, and if you are offloading cost you have to bill each homeowner...

jpmattia 12y ago

> While this is pretty cool, due to distance limitation we are not getting telephone line modems that can outstrip fiber optics. I doubt anyone is under any illusions that the copper is going to outstrip fiber. However, it is still an important result: There are many places that are stuck with old-fashioned twisted pair and it takes literally an act of gov't to lay down fiber. Rather than leaving that population out in the cold, this result gives hope that they may have cutting edge connectivity. The real issue is commercializability, which has not been Bell's traditional strength.