

Joseph Lechleider, a Father of the DSL Internet Technology, Dies at 82 - danso
http://www.nytimes.com/2015/05/04/technology/joseph-lechleider-a-father-of-the-dsl-internet-technology-dies-at-82.html

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danso
For those who think being older than 30 is the end of innovation as an
engineer:

> _Mr. Lechleider’s insight about how to increase data speed came when he was
> 55. He had spent decades studying signal processing, so he was deeply
> grounded in the field. But Mr. Lechleider, according to Mr. Cioffi, was
> something of an iconoclast in a large, often bureaucratic organization. “He
> was not afraid to take a risk and fight for a new idea,” Mr. Cioffi said._

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richardwigley
>> "When the data speeds in both directions — downloading and uploading — were
the same, there was a lot of electrical interference that slowed data traffic
to a crawl.

>> ... such meddlesome interference — known as electrical crosstalk — could be
drastically reduced if the download speeds were far faster than the upload
speeds."

Cool, so DSL is prevented from increasing the upstream traffic by the physics
- not a matter of upgrading the 'boxes' at each end of the wire.

~~~
skrause
This problem has been solved by VDSL2 for quite a while:
[http://en.wikipedia.org/wiki/Very-high-bit-
rate_digital_subs...](http://en.wikipedia.org/wiki/Very-high-bit-
rate_digital_subscriber_line_2) \- the ratio of downstream and upstream and be
configured freely there. Using VDSL2 with vectoring you can now get
connections with 100 Mpbs downstream and 40 Mbps upstream in Germany.

~~~
poizan42
> LR-VDSL2 enabled systems are capable of supporting speeds of around 1–4
> Mbit/s (downstream) over distances of 4–5 km (2.5–3 miles), gradually
> increasing the bit rate up to symmetric 100 Mbit/s as loop-length shortens.

You need to be quite close to the exchange to get the higher speeds. Sounds
like it should be a solution to the last mile problem though - strategically
place DSLAMS along the fiber where existing copper can be re-routed to it. I
have no idea how much this is done.

