no dial tone but dsl works

[slag]

Last weekend I lost dialtone on my home phone. People calling got a busy signal and there was just dead air on my side.

DSL went out for approx 6 hours but came back. Every once in awhile it would lose signal and reaquire but not too often. It was stable enough for me to play WoW.

Phone company came out and discovered my neighbor had burned some brush behind his property and it heated up enough or burned through my cable enough to interrupt my service. Phone line is only 1 foot below ground.

My question is, if dsl requires a much better line than just voice service (i.e, copper vs aluminum wire), then how could DSL still work and my voice service not?

Obviously it wasn't burned clear through but it was damaged enough so I had no dial tone.

Slag

 

[SampSon]

DSL doesn't require a dial tone.
DSL doesn't require a "much better line" than voice service.
DSL works with two poorly connected pairs.

 

[slag]

everything ive read at dsl reports seems to point that dsl requires a relatively noise free line with good signal attenuation (i.e, good line). I had the 6 mb service as well which requires very little noise.

Just seems weird that i had no voice service but had dsl but i'll take your word for it.

 

[MichaelD]

Originally posted by: SampSon
DSL doesn't require a dial tone.
DSL doesn't require a "much better line" than voice service.
DSL works with two poorly connected pairs.

/qft
/thread

DSL operates at much higher freqs than you can hear. Electrical connectivity, NOT voice quality will determine your DSL quality. Distance to TELCO plays a huge role as well.

 

[slag]

looks like i was mucking the info I got from this thread:

http://forums.anandtech.com/messageview...atid=50&threadid=1915469&enterthread=y

Yup... voice phone is bandlimited to 300 - 3300 Hz, so it doesn't need much quality. DSL runs at much higher frequencies, so it needs high enough line quality to get a signal through; I'm sure they could use it somehow still, but it probably wouldn't get enough bandwidth to be worth much more than a regular modem.

 

[Mark R]

Yeah - this exact problem happened to me.

Phone and DSL are supplied seperately in the exchange - the two services being combined via a device rather like a microfilter before leaving the exchange. If the fault is wiht the phone equipment, then this would give the symptoms you describe.

Another possibilty is the fact that there is a high-resitance (line break), in one of the wires supplying the service. Phones need a DC power supply (about 48 V) supplied by the exchange, and operate on low frequencies. DSL, operates only on high frequencies (and DSL equipment runs on its own power).

If there is a break in the line (yet the two ends are in very close proximity) - e.g. the copper core in a wire breaks, but the insulation is intact - it can act as a capacitor. Capacitors block DC and low frequencies - but are pretty much transparent to high frequencies. So, in this case, a line break would stop the phone from working, but the DSL may continue working (although it would likely be degraded somewhat).

Interestingly, if a line-break or high-resistance problem is developing on your line, you will often get noise on the phone service when the DSL is active (exactly as though you had not connected a DSL filter). This is caused by the damaged part of the line distorting the high-frequencies of the DSL, with the distortion appearing on the line as low-frequencies (which are heard on the phone line).

 

[dmcowen674]

I'm impressed young whippersnappers, you have learned well. :thumbsup:

I was expecting to see someone like the President of BellSouth Louisiana to come on and say "It's not technologically possible to supply DSL without Voice service"

That was Mr Williams exact words.