DSL-Extender Brings Broadband 20km

An anonymous reader writes "Whirlpool outlines Telstra's new DSL deployment: "Telstra announced a trial of the technology back in January, saying it would allow DSL to be connected to people who were up to 20km from a central exchange. DSL Extenders work by splitting an existing copper phone line into eight separate ADSL lines using a tiny, ruggedised remote DSLAM.""

Comments

Remote DSLAMs

[Phroggy]

Remote DSLAMs are certainly nothing new, but usually the connection from the remote DSLAM to the CO is fiber, not copper.

Newer housing developments sometimes have a fiber line that runs into the neighborhood, then copper lines from there to each house, so the phone company doesn't have to run a big bundle of copper all the way back to the CO; a remote DSLAM is the only way to offer DSL to these houses.

What I want to know is, how did they get a reliable 2.3Mbps link to work over 20km of copper?

Re:Remote DSLAMs

[Macfox]

Telstra are already using this MINIMUX technology. In many new housing estates they have installed RIM units (on the cheap) where there wasn't enough copper back to the exchange.

When the residents discovered they couldn't get ADSL in the brand new mega expensive developments, Telstra backflipped and took two years to addressed the issue with the so called MINIMUX (Mini DSLAM). They're still rolling them out as we speak.

Having said that, even if your on a RIM voice service, you can't get access to other providers, only Telstra (wholesale). So you're still at the mercy of Telstra's premium pricing.

Re:Remote DSLAMs

[elgatozorbas]

Copper: great for POTS, crap for data, ubiquitous. So they invent DSL to compensate for copper's inadequacies.

They invent DSL because copper is ubiquitous. Why do you think the fiber was put there in the first place? Exactly to have a headend for either DSL or cable.

Fiber: crap for POTS, great for data, ubiquitous right up until the end of the street. DSL doesn't work because its a copper technology, so these poor people who are feet away from all the broadband they could ever need can't access it because telcos only know how to do DSL.

In a FTTC (fiber to the curb) system the DSL modems are right in the cabinet at the end of the fiber you mentioned.

I'm not oblivious to the fact that it costs more to split fiber (light doesn't split like electricty), but thats because we don't do it very often as the priority has always been POTS. How long will it be, now that data outweighs POTS, until we get fiber to the front door?

The problem is not technological in nature: neither light nor electricity is 'split'. The connections are point-to-point (between modem and DSLAM), so there is no splitting involved. The real cost is in guys digging trenches to put the fiber (and obviously the fiber and installations themselves).

Re:Remote DSLAMs

[Anonymous Coward]

In the USA, most existing DSLAMS are connected over copper. It was initially a way to avoid 'copper starvation' during buildouts in developed areas. Instead of feeding new trunk lines out from the CO, you drop a pedestal and split two pair among 24 or 48 POTs lines. Pair gain, in the sense that two pair carriers now become 48 pair at the DSLAM.

This was going on long before fiber became as popular as it is now. New DSLAMs are likely to be fiber feeds, but the existing base is copper for historical reasons. If a technology allows higher data density over copper, then the upgrade to the provider is simply to fork lift out the old DSLAM and replace it with a more capable unit. No need to run fiber to get the new capability.

That rate over that distance has been in the labs for quite a while. The issue is not the difficulty with the data rate over the distance, the difficulty is doing that without interfering with adjacent pairs in the cable. Receiver sensitivity and noise margin/rejection has apparently solved that problem.

With some of the new wireless technologies coming on in the next two to three years, wired/fibered broadband for anything slower than 3Mbps is going to go the way of the dinosaur in any case.

And 3Mbps addresses most of the user base for data access. Particularly in rural areas where there might be 1000 ft between houses, high speed wireless makes a lot more sense from both capex and opex.

Australian Broadband...

[Macfox]

A few facts

Oz Broadband is anything over 128kbs.(ISDN) Laughable yes.

The maximum speed Tel$tra offer (over ADSL) is 1500/256kbs. *

Up till this announcement, if you were over ~3.5km from the exchange, then you probably couldn't get ADSL.

Telstra (Bigpond) charge for data usage in both directions and their largest offering is 10GB, with modem speed shaping there after.

Telstra also force voice bundling. If you want ADSL, you must have voice and pay a minimum of $18.50AUD per month, even if you don't need it.*

This new offering is best described as a mini DSLAM with a ~2.3Mbit backhaul. So even two users could potentially max it out.

While it's good news for some that are out of reach. The overall state of Oz broadband isn't worth writing home about.

* Some providers offer connection without a voice service (ULL) and ADSL2+ (24Mbs) but only in 5% of exchanges.

Greedy is global

[noisymime]

ohh don't worry, Australian Telcos (Especially Telstra) are greedy bastards as well. Its just that they're being strongarmed by the government to provide reasonable service to remote areas. Its a shame they're not being forced to do it at prices that are inline with the rest of the world.

Re:More info?

[arrow]

What this amounts to is moving the DSLAM from the central office to the pole outside your house, then wiring one or more T1/E1 lines to it.

No magic "sprinkle this on your phone line and wait 10 minutes" here.

There is nothing stopping you from deploying "this technology" for yourself today. Except maybe sticker shock. You'll shell out $500+/mo for the T1 line (since you don't already own the lines, like the Telco does), a couple grand for a DSLAM, and ~$100/mo in fees for dry pairs (assuming they even let you order them anymore) to your neghbors houses if you want to be nice and share.