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Comment by RicoElectrico | Hacker News Reader

Wait, can DSL modems talk to each other instead of a DSLAM line card?

Not a traditional dsl modem, but these work well using dsl technology: https://www.amazon.com/Tupavco-Ethernet-Extender-Kit-Repeate...

I was about to point something like this out.

That's pretty cool. The specs look like this is both faster and cheaper than the main link of this thread, unless I'm missing something?

According to the description this adds at least 660ms of latency, so might be useless for certain applications. Wonder how much the TFA solution adds.

Its true that the specs are not symmetric in ADSL. The CO (Central Office) end is different from the CPE (Customer Premises Equipment) end, and two CPE devices cannot talk to each other. Among other things, the engineering work had to take into account that at the CO end a bunch of wires would come together and leak RF between each other.

G.SHDSL is more common in a 1:1 configuration (although I think the ends may still be not symmetric) because it was designed as a T1 replacement.

However some devices that could do a single line of CO were made, that can therefore talk to a CPE.

Some can at least. I used Netopia SDSL routers without a DSLAM around twenty years ago to serve "high speed internet" in town in the US (Easton Maryland) a few years before they managed to get municipal broadband.

It used to be possible many years ago, when I had a DSL modem as PCI card. There was a windows software that would put it in "server mode", and then you could connect another DSL modem to it and "dial in". Not sure if this is possible anymore, but there are Ethernet repeaters that are based on DSL tech which should work in a similar way.

Most SHDSL and some VDSL can talk each other indeed. Used that capability a lot in 200xs.

They may be using the term "modem" loosely here, or rather, more generally than "home modems".

https://en.wikipedia.org/wiki/Modem

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