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[snapty00]

Why is this? Why does DSL have these x amount of feet limitations from the central office, while cable connections don't seem to suffer this problem?

 

[ShadowRed]

Cable is designed to carry data over longer distances. It was built from the ground up that way. DSL comes over phone lines and when they put in phone lines back in the day they didn't take into account that it would be used to carry anything other than analogue(sp) signals.

 

[snapty00]

Hmm. So is it the cabling itself only?

 

[jenov4]

Q: Why is distance important with DSL? (#4676)

A: If you have heard even something about DSL, you will have heard about distance. Your phone lines normally terminate at a telco office, usually nearby. This distance, (the length of your line between your location and the telco office), is a very important factor in whether or not you can get DSL, and what speed you can get.
Here are some rules of thumb for distance ranges. Please be aware that especially with non Telco ADSL lines, distance limits for speeds can vary widely from company to company. There are cases where it is policy for "residential" DSL lines not to be offered as far out as functionally identical "business" products!

Read the rest here: http://www.dslreports.com/faq/4676

 

[snapty00]

I pretty much understand why there are distance limitations with DSL, but I don't get why cable doesn't have the same problem.

 

[Dilbert]

A short bit of physics: Copper telephone wire is intended to carry voice communications, which are in the 300-4000 Hz range. Any electrical signal in a copper wire will attenuate (lessen) as it propagates -- the farther it travels, the greater the attenuation. In order to provide voice service at large distances, the phone network includes repeaters which "echo" the signal at a higher amplitude to combat attenuation.

DSL, which is a higher-frequency signal transmitted simultaneously over the same copper wire and filter out of the audible range with a bandpass filter, has a couple things working against it. The biggest problem is simple physics: The higher the frequency, the greater the attenuation over a given line length. So, over that 10,000 feet between you and the local exchange, you will lose far more DSL signal than you will voice signal. Also working against it is the effect of repeaters and other "noisy" elements on the line: The DSL signal must be decoded to access the information, but line noise can contribute to unrecoverable errors, which also contribute to limiting the effective range.

 

[snapty00]

A short bit of physics: Copper telephone wire is intended to carry voice communications, which are in the 300-4000 Hz range. Any electrical signal in a copper wire will attenuate (lessen) as it propagates -- the farther it travels, the greater the attenuation. In order to provide voice service at large distances, the phone network includes repeaters which "echo" the signal at a higher amplitude to combat attenuation.

DSL, which is a higher-frequency signal transmitted simultaneously over the same copper wire and filter out of the audible range with a bandpass filter, has a couple things working against it. The biggest problem is simple physics: The higher the frequency, the greater the attenuation over a given line length. So, over that 10,000 feet between you and the local exchange, you will lose far more DSL signal than you will voice signal. Also working against it is the effect of repeaters and other "noisy" elements on the line: The DSL signal must be decoded to access the information, but line noise can contribute to unrecoverable errors, which also contribute to limiting the effective range.

Okay, but aside from the simultaneous voice signal, why doesn't cable suffer from the same problem? Don't they have to be run long distances, as well? I know of cable lines that run significantly farther than 15,000 feet. That's basically what I'm asking.

 

[Dilbert]

Okay, but aside from the simultaneous voice signal, why doesn't cable suffer from the same problem? Don't they have to be run long distances, as well? I know of cable lines that run significantly farther than 15,000 feet. That's basically what I'm asking.

Coaxial cable DOES have distance limitations, especially compared to optical fiber. However, the shape of the conductor (coaxial versus twisted pair) provides a smaller attenuation and higher resistance to interference than DSL...and therefore a longer effective distance.

 

[snapty00]

Coaxial cable DOES have distance limitations, especially compared to optical fiber. However, the shape of the conductor (coaxial versus twisted pair) provides a smaller attenuation and higher resistance to interference than DSL...and therefore a longer effective distance.

Argh, I wish they'd use coax rather than UTP or STP, then, especially if it'll increase the distances by that much.

 

[ChumsGum]

Don't worry about it too much. In the next few years, the Telcos will bring fiber optic lines closer to your home. They'll soon offer voice, data, and television through your phone lines without the need to retrofit your home.

 

[alejob]

Well, coaxial cable has a shield, phone lines don't. Phone lines have 4 copper wires, thats causes cross-talk which is basicaly interference between the wires.

Also UTP is capable of faster transfer rates than Caoxial. And phone lines are not UTP.

 

[nitewulf]

Argh, I wish they'd use co-ax rather than UTP or STP, then, especially if it'll increase the distances by that much.

jinx pretty much explained everything. its basic electromagnetics. the coax cable used for cable services are just better signal transmitters. the signal can carry farther, ie, has less attenuation plus you get more bandwidth, ie, it has a higher cut-off frequency, you can send faster (higher freq) signals using co-ax.

 

[NohWun]

Well, coaxial cable has a shield, phone lines don't. Phone lines have 4 copper wires, thats causes cross-talk which is basicaly interference between the wires.

Also UTP is capable of faster transfer rates than Caoxial. And phone lines are not UTP.

One phone line is one unshielded twisted pair of wires (or UTP). The default 4 wires sent to homes allows for 2 lines. Having the wires twisted provides for resistance to noise and crosstalk.

In general, coax allows for higher transfer rates than UTP. In addition, coax connectors and such are all designed to minimize noise, whereas UTP junctions usually aren't as well designed.