ADSL Line Extenders

A friend on a rural DSl association asked about ADSL line extenders.

A search on Google yields many products dating back to the days of
ADSL-1 advertising 1mbps profiles, but a few seem more recent and
support ADSL2+ (not sure if any support VDSL2).

Are these thing out of date and no longer deployed ? Were they ever
effective, or just vapourware that didn't really improve things ?

Do any Telcos still deploy them ? Anyone know of deployments in Canada ?

I just need a reality check on those devices.


Wikipedia[1] suggests they're a real thing, and have real-world uses. I can
imagine that a big disincentive to installing them would be powering them,
although line power would probably be enough for one or two hops. Getting
access to the line in the right places to install them might be a challenge,
too (or at least be somewhat expensive). No doubt telcos also don't want to
install them because they can make a whole lot more money for less effort
by forcing customers onto wireless.

- Matt


I know a couple of LECs that use these with success:

They're certainly real, still in use, and deployed world wide but most
commonly in rural areas. They aren't particularly cost effective for most
scenarios, but cheaper than hanging even a mini-DSLAM to service 1-2
customers that are too far away from a cabinet. Installing them is a pain
and keeping them running long term is an even bigger pain. Certain models
don't work well with specific DSLAMs and/or in specific plant combinations
so testing with your DSLAMs, modems, and in your plant is a must.

Scott Helms
Vice President of Technology
(678) 507-5000

You can get adtran 1248b's that run ADSL 2+ for less than 2k still. Then get Cisco 887s as end points. That's what I run. 8 meg at 3 miles or so.

I am not sure if they make a VDSL or not, but would check them out.


Semi-related question: in instances like this, wouldn't a point-to-point
link provide larger throughput and be less expensive? Unless you are
talking about several subscribers that are already installed and operating.
Depending on the situation, it might make sense to set a few sectorial
antennas at a high-point and link everyone with small inexpensive CPE
antennas. Just a quick thought.

Good luck,

I second wholeheartedly the idea of wireless for this application, except that Rafael probably meant point to multipoint solutions: Trango or Waveip are 2 good options.

Line extenders supporting ADSL2+ won't do much good: the 2 and the + denote improvements in the short range, less than 5000', probably not relevant in your case. If wired is your preferred option, you might want to consider HDSL based products, which are meant to drive 1.5M symmetric over long distances, power fed from the 2 sides for simplicity, with ability to go higher when pairs are bundled. Adtran should be the 1st place to look at.

Good luck, Shimon

Yes, you are correct, P2MP is what I meant to say. I'd also suggest
Ubiquiti radios, some of their models being capable of doing 1gbps+.

1Gbps Aggregate.

AF24/AF24HD are ~ 750Mbps/750Mbps at max modulation. That is a PtP system though, not PtMP.

If you need to carry ADSL traffic, you most likely need a "timing-enabled" (can't remember the RFC) radio. RadWin and Trango should fit the bill, likely others.

Honestly though, I'd ditch the ADSL if possible. Depending on the terrain, wireless may work. It's not magic, and won't shoot through acres and acres of trees, but if you have a good line-of-site (60% clear 1st Fresnel zone), those are prime subscribers for 5GHz Ubiquiti Rockets + Sectors and ~$100 CPE devices. Don't put more than 25 or 30 subscribers per sector, and you can easily hit 10Mbps per sub with a modest oversubscription ratio. If you went for the RM5-AC line in PtMP, you might be able to do 40Mbps per sub.

Josh Reynolds

I want to thnk those who answered in this thread. It has provided me
with some insight.

There is an upcoming review in Canada of the "basic service objectives"
with questions on how best to deply in rural areas. (My own opinion is
that in 2015, if you're going to deploy something, it might as well be
FTTH) but gives me enough info to ask questions about DSL extenders and
of the incumbents would/could of have considered using those.

Can't run fiber everywhere.

(I am the CIO of a W/ISP in Alaska)