qworster
join:2001-11-25
Los Angeles, CA
 ·DSL EXTREME
·Brand X Internet
 ·RoadRunner Cable
 ·Vonage
4 edits | The bottom line is this: DSL signal levels get weaker as the wire length from the DSLAM (located in either a central office or a remote terminal) gets longer. The technical term for this is attenuation. Attenuation is measured in db (decibels).
One of the big things that affects DSL signal quality is CROSSTALK. Crosstalk is just that-the signal from wire pair X leaking into wire pair Y. See, all telco wires are bundled into a cable. It's not uncommon to have 500 or more copper pairs bundled into one big cable.
Now, let's assume that the CLEC only has access to the DSLAM at the phone office. The DSLAM puts out a +10 dbm level. One mile away there's a FTTN node that the Central office cable goes through. By now, the loss in the copper pair has reduced the DSL signal by 30 db to -20 dbm. BUT...Qwest has put their OWN DSLAM right in that node box-which is putting out +10 dbm to a copper pair that runs right next to the pair that has (now) the -20dbm level. If the crosstalk coupling between pairs is 50 db, this means that there is an interfering signal sitting only 20 db below the desired DSL signal. Any additional pairs that are active from that cabinet will degrade this by 3-6 db more per additional pair. Put +10 dbm DSL signals on 15-20 adjacent pairs and the interference will be HIGHER (louder) then the desired DSL signal itself! This means that the CO based DSL circuit will no longer work.
Don't think that this can happen? Of course it can-especially when we consider that the very REASON that FTTN box was installed in the first place IS to get strong DSL signals to the homes, so Qwest can offer very high speed Internet and/or television (video) over IP.
There is a simple way that Qwest can fix this problem-allow the CLECs access to the FTTN located DSLAM. That way EVERYONE will have the same signal levels all the time.
The fact that Qwest won't do this shows their ulterior motive-to bully the CLECs out of business.
In simple terms:
Qwest = scum
Disclaimer: I was a former Qwest customer/victim; hence my handle!
Qworst: Ride the LIE! |
