Hacking the Actiontec 56k Modem/Gateway

william_lorenz writes "The Actiontec Dual 56k External Modem is an inexpensive device with a built-in 56k modem and two Ethernet ports that can be used as an Internet gateway of sorts. What's great about it is that it runs some form of uClinux, it's easily hackable, and Greg Boehnlein of the Linux Users Group of Cleveland and NOOSS fame recently contributed a detailed report on his findings! Pictures of the board are also available here, here, and here. Lots of specific details are included in Greg's article, and there's been some further discussions about this on the LUGC mailing lists."

Comments

56k gateways

[Sir Haxalot]

are almost pointless, a 56k connection is bad enough without it being shared across several computers.

Re:56k gateways

[mackstann]

Two ethernet ports + linux + easily hackable = who cares about the modem jack?

Re:56k gateways

[zakezuke]

56k is better then nothing. Keep in mind also the fact that primarly text information gets compressed unlike in broadband technologies. Keep in mind that many a small business or small remote office doesn't nessicarly need lots and lots of bandwidth just to get e-mail.

Hackability? Well I'm somewhat curious what they can do with such a device. The first thing that comes to mind is a standby gateway that goes online when the primary gateway fails. This would be MOST handy.

Re:56k gateways

[MadX]

Hmm .. perhaps in your country. In South Africa, this is basically the standard .. sure you have ISDN / ADSL ..
BUT

ISDN - very expensive to start with (+- R2000-00 initial startup @ R 7.50 / $1) then you still pay for the call charges. If the config goes haywire you can end up with a bill of R 4000-00/month.
ADSL is only available in certain areas - but there is a 3gig monthly cap. some guys can go through that in a day if they wanted to, and the service is being oversubscribed so quickly that the transfer rates are becoming dysmal. The only advantage is the 24x7 online connectivity (although they say that this is not guaranteed)

So most subscribers pay for 56k access (and we do pay for every local call made)

Maybe once the monopoly is broken (ie: SNO) there will be some sort of relief for the south african public ..

Re:56k gateways

[Anonymous Coward]

A NATted LAN is certainly better than nothing when you're sharing a house with multiple machines. Yes, it's slow if two people are using it at once, but it also means you don't need a modem in each box, don't need to risk someone else trying to dial out with another machine while you're already connected, someone can sneak in a quick Google or mail-read around your activity (or, in my case, I could stay on IRC while others browsed to their hearts' content)... ...But most importantly, it's a dramatic convenience when working with *NIX machines, and other software/projects that assume use in a LAN environment. Yes, you *can* net-install OpenBSD overnight on a 56k link - but you'll need to be ethernetted to do it, since they didn't fit ppp on the install floppy.

Now, I can see some vague utility for this hardware in the SOHO market, though I can't tell if it's configured for same by default (the marketing and 'modem' branding suggests not):

A lot of small businesses rely on DSL or Cable shared through a simple Linksys, but should there be an outage, their LANs are dead in the water. With a modem *in* the dinky embedded router, they'd have the option of falling back to dialup rather than closing up shop or waiting for their MCSE to get to dealing with it. With the appropriate firmware load, one of these things could provide fully automatic failover - and "failback" when it detects the DSL or cable has returned.

Many businesses I've met have been confused into paying for a full unused phone line/number 'beneath' their DSL anyway, so this would improve their uptime without adding to their costs. True, the same could be done with a dedicated *NIX machine, or even Windows ICS, but not everyone has technical staff on hand, and it'd be cheaper to have a contractor drop in $100 of 'foolproof' hardware once than stay on-call for care-and-feeding of a less "embedded" solution.

Re:56k gateways

[screenrc]

I have worked on such uClinux gadgets (for pay); although I have not bothered to read about this product, it should be safe to make these observations:

1. Two posts only? That is not very useful at all. You probably need a hub as well.

2. uClinux is not readily hackable, at least until you drift of it, and also know how to recover when this thing freezes. You can not just dive into it as if it was a linux PC.

3. The modem is probably the *best* part, but that has been done for many, many years. Nothing special.

If this thing had more than 2 eth ports, it could be useful; but, I would rather have it wirelss.

Re:56k gateways

[gr0ngb0t]

similar deal here in australia, where we have a nutjob Minister for Communications, Information Technology and the Arts who thinks that pornography is one of the major reasons why there's been a high take-up rate (of broadband) in South Korea and uses this (and a belief that kids only want broadband access to play games) as a reason to not fund, or agitate for, improved broadband access here in Australia.

You pay through the nose for a shitty service, and until they fix that, both in price and reliability, I'll stick to abusing my work bandwidth and stay with the trusty old agravatingly slow, but unlimited bandwidth, 56K dialup for home net access.

At least with a dialup deal, I can set up bulk downloads of whatever (no i'm not a p2p junkie) and leave the auto-redialer on to re-connect when i get disconnected. i'd rather that than have to pay A$80+ for a decent home broadband connection.

Re:56k gateways

[Jason1729]

If you're doing big downloads, 56k is already painfully slow, so this will only make it worse.

For typical websurfing you spend most of the time reading a page and a small portion loading new pages. It seems like both users downloading a new page at the same time will only happen occasionally, so most of the time, they can share the 56k connection without even noticing.

On the rare occasion where both users do load a page at the same time, it's still working at half speed, so it's not a major problem for how uncommon it is.

Jason
ProfQuotes

Re:56k gateways

[Anonymous Coward]

this is not a modem sharing thingy! this is a cheap single board computer that runs linux, has two ethernet ports and a modem, probably some other digital/serial io. (boxed, with psu, etc) that runs linux!!! perfect candidate for a web thermometer, ethernet garage door opener, robot brain, home weather station controller, etc.

Re:56k gateways

[nettdata]

are almost pointless, a 56k connection is bad enough without it being shared across several computers.

Almost, but they still have their uses.

I was the IT Manager for Lilith Fair, and when we sent the tour buses out on the road, 2 of them were dedicated accounting buses with LANs, printers, etc. We couldn't be guaranteed any kind of broadband connection at our stops, but we WERE guaranteed just about as many POTS lines as we could handle.

We set up two similar devices, one on each bus, and they were very simple for the non-technical accountants to use. It should also be mentioned that each device had 2 56k modems in it, and they attempted to do some sort of load-balancing or connection "stickiness" to take advantage of the dual connections.

They were perfect for sending and receiving emails, and even remote-faxing. We also used the same connection to synch up a couple of Oracle databases.

We quite liked them. (They weren't the same devices mentioned, but quite similar).

Re:56k gateways

[L10N]

Wow, a great post from someone that has English has a fourth or fifth language, or maybe from someone either drunk of his ass, or too damned lazy to spell check and use correct grammar.

Pot...Kettle...Black...

Re:56k gateways

[dreamchaser]

I know that others have disagreed, but I had to add my ten cents. It is not worthless. A lot of people seem to forget that the vast majority of people do not have broadband yet. Until we were able to get it I used a single 56k line to share with my family. For web browsing and email it worked, though I'd usually disconnect everyone else when I wanted to play Quake.

No, it isn't very fast and the latency is rather high, but it isn't at all pointless. It works quite well actually.

Re:56k gateways

[Daniel Phillips]

ISDN - very expensive to start with (+- R2000-00 initial startup @ R 7.50 / $1) then you still pay for the call charges. If the config goes haywire you can end up with a bill of R 4000-00/month.
ADSL is only available in certain areas - but there is a 3gig monthly cap. some guys can go through that in a day if they wanted to, and the service is being oversubscribed so quickly that the transfer rates are becoming dysmal. The only advantage is the 24x7 online connectivity (although they say that this is not guaranteed)

So most subscribers pay for 56k access (and we do pay for every local call made)

That pretty much describes the situation in Germany, up until two years ago. Barbaric. The weird thing is, the locals just never understood how badly Deutsche Telekom was abusing them until broadband came along and made it perfectly obvious how far the country was going to fall behind if things didn't change fast.

Local calls still carry toll charges, it's so stupid, as if the bandwidth needed to carry a voice call actually cost anything measurable these days. It's also still pretty much impossible to get flat rate 24/7 dialup access, as Canada has had since about 1995. So if you aren't in an urban area, you are still a digital hillbilly, you connect to the internet only on special occasions.

Re:56k gateways

[Effugas]

A little humility, Tom? :-) There are some people who've been in this game even longer than we have.

You actually haven't lived through it all. Neither have I. (Backstory: Tom and I are friends.)

What he's referring to is Frame Relay -- the method by which X.25 networks (telenet/tymnet, for the Delphi/Source/Compuserve/GEnie folks of the mid 80's) propogated their traffic, and ultimately the way most nationally dispersed data centers exchanged their data. Those networks didn't run on modems per se (they didn't convert signals into something that ran over POTS), but the converters that interfaced local hardware to the telco's 9600bps line could almost certainly cost $10K -- it's a simple matter of small market, large investment in R&D, and, oh yes, a monopoly too :-)

CSU/DSU's for T1's aren't cheap either, even with SDSL modems running a couple hundred dollars.

Incidentally, this isn't even a thing of the past. It turns out 56K Frame Relay links live on. I know of a _massive_ corporation that links most of its stores to the central mainframe via 56K FR links. Why? Because It Works.

--Dan

Re:56k gateways

[Sleepy]

>>2. uClinux is not readily hackable, at least until you drift of it, and also know how to recover when this thing freezes. You can not just dive into it as if it was a linux PC.

>You have never worked on any embedded system, for pay or otherwise.

Be nice. I think what the author says is true... from the average Linux hacker's perspective, an embedded platform is NOT readily hackable.

Plus he will have no documentation from the manufacturer. The manufacturer likely modified uClinux and possibly BusyBox in some undocumented manner, to "save space".

I just finished a project where I added some CGI GUI's and a dynamic DNS client to a webcamera with embedded Linux. I couldn't have done it if it was not Linux inside, but it was a bear. When you don't know "what works" on an OS variant, trial and error gets old real fast...

Re:56k gateways

[lucifuge31337]

Incidentally, this isn't even a thing of the past. It turns out 56K Frame Relay links live on. I know of a _massive_ corporation that links most of its stores to the central mainframe via 56K FR links. Why? Because It Works.

While I'm sure you are aware of it, I doubt many others are: 56k frame and 56k analog dialup are fantastically different in actual performance. A 56k FR has very low latency, which makes interactive apps (like telnet and SNA crap, the bulk of the traffic I see still going over these links) very much usable. Try that with a modem and the latency makes it very difficult to tolerate with multiple users.

Re:56k gateways

[Jennifer E. Elaan]

Well, the thing is that the device is a simple ARM-based single-board computer with two ethernet ports and a modem. It runs uCLinux. Anything you can cross-compile and cram into the flash, it will support.

It should be relatively simple to set up, say, PPPoE on one of the ports, a connection to a LAN on the other. Then write a simple script that watches the PPPoE connection status, and dials the modem if the PPPoE has been unable to connect for a certain amount of time.

The device would obviously have control of its own default gateway, which would solve that issue. Would the failover be transparent? Not quite, open connections would break. But it is simple, and would provide service through a DSL blackout.

Re:56k gateways

[yomegaman]

If they're running Windows they could set up Internet Connection Sharing. That's what I do when I visit my parents. My dad's PC connects to his ISP using the modem, and I bought a cheapo wireless adapter and have his computer share the connection through that to my laptop. It's really easy to set up and works pretty well. That way I can use my laptop at the kitchen table without having to run phone cords all over the place.

Nice machine

[jmorris42]

Looks like a nice machine with default software that is a bit lame. But since that is now easily fixable, I can think of a few folks in dialup hell that I'll probably be crossing off my Xmas list. :)

Let the comments begin!

[Anonymous Coward]

Jeez...

Slashdotted already.. this article's gonna set the record for redundant posts.

Yes, we KNOW his server MUST be behind that 56k modem.

Right, now that we've got that out of the way...

Hmm... other products

[Empiric]

Personally, I'm more intrigued by the company's anti-kidnapping technology. I'll sleep easier once that's out of the way.

Sponsored by AT&T

[madsen]

From the ActionTec site:

the External Dual PC Modem keeps you connected longer, and faster.

They say it's hackable

[Anonymous Coward]

"it's easily hackable"

If only we could hack it into a 256k modem...

Re:They say it's hackable

[Anonymous Coward]

It's not really the FCC's fault. They imposed the limitation due to the potential for crosstalk due to the nature of the lines themselves. That said, specifying it in bits/second was a dumb way to go about it (and no doubt suggested by the telcos) -- at least, I think that's how the rule is written. So, back in the days when switching was still physical, it would be likely that, were everyone using these hypothetical 256k modems, you wouldn't be connecting near the full speed due to all the interference, and voice service would be degraded for everyone.

But in any case, *since* the regulation was put in place, this allowed the telcos to move to digital switching, since they could know the limit of the signals they'd have to digitize to support all legal users/devices on their circuits. You have to admit, it would've been hard for them to carry on any other way -- Imagine if they still had to support racks of relays just to ensure your attempt to run ethernet-over-phoneline would work. Now imagine if they had to try to support that for *long distance* calling...

Now, DSL is a little different. For one thing, it terminates at the telco's central office racks, or a 'remote terminal' (basically a central-office-in-a-box that connects back to the main office over fiber or some extreme-speed-over-copper solution), so the telco only has to support line quality over a limited, known distance. For another, it takes advantage of technological advancements to run up in relatively high, definitely inaudible frequencies*, so there's little risk of corruption to others' voice service... and further, the hardware is, in fact, advanced enough to pick from any of a number of 'channels,' such that, while it's still only a point-to-point tech, it can avoid crosstalk from your neighbor's link by running on completely different frequencies. Practically speaking, it *is* the best thing telcos can bring you right now over existing copper && at a vaguely affordable price && while being profitable enough for them to continue deploying it.

Now, in exchange for this non-switchability (you aren't "making calls" with DSL, it's basically like having a big fault-tolerant null-modem cable between you and the terminating equipment), the telcos are supposed to open up their racks at reasonable cost so other ISPs can come in and give you a choice of whose service you're plugged into. Yes, this part has been getting a bit screwed up, but that's a political issue; it's hard to imagine it working another way technologically... unless they'd done something like electricity 'deregulation,' and set it up so you'd *always* be using the telco's equipment, backbone, netblock, etc., and choosing which ISP to pay the equivalent of your 'generation charge' to. If you think about it for a moment, you'll realize that'd work roughly as "well" for telecom as it has for electricity, so perhaps it's a good thing they didn't try it that way.

So the real question is not, "Why do we have to buy DSL instead of 256K modems?," it's "Why do we still bother with 'voice' circuits at all, when everything could be 100% digital and routable, with Vonage-style boxes at the NID of the homes?"
It's 2003, and it'd make the most sense for the telcos to become 'data utilities,' in competition with cable, wireless, and third-party fiber-stringers... ...but we're still in a transition period, and since the telcos *will* leap like rabid weasels to price-fix and destroy competition if they're let off their leashes, it's not clear what we can do. The same regulations that *allow* competition for DSL (forcing 'open racks') make it unattractive for the telcos to offer DSL without the underlying, obsolete voice circuit - because then the ILEC wouldn't be getting their cut (or at least, as big of one) if you opted for a CLEC's service.

Meanwhile, of course, cable is practically unregulated, so you get your local monopoly with that, and absolutely no ISP choice (which would be technically 'expensive' anyway, giv

why not just buy a mini itx?

[Anonymous Coward]

although a bit larger, you can shove a mini itx board into just about anything. and you can have full on linux & routing capabilities.

Inexpensive?

[camilita]

If you dont need bells a whistles a 56k modem for more than 50+ bucks seems a bit pricey. There are plenty of linux "compatible" modems for less than 30 bucks.

Re:Inexpensive?

[EnglishTim]

I think the point is that it is easy to connect two computers to the modem via the ethernet ports if you don't want to have to set up internet connection sharing on one of your computers.

Re:Inexpensive?

[Damin]

The purpose of the article was to demonstrate how the box can be modified to fit your own needs with the hopes that others will take the initiative and explore. This box is an awesome introduction to embedded computing platforms at nearly 1/4 the price of DIY boards. The fact that it actually is usable as a gateway is not really relevant, nor is the comparison of adding a modem to a Linux box. You won't learn a thing about embedded Linux by adding a modem to your box.

possible to hack cable/adsl routers?

[narkotix]

Would it be possible to hack an adsl/cable router to be used as a simple webserver? For a low traffic and static site it would be perfect for my business website hosting needs. 10watts consumption...fanless operation...and small footprint it sounds like a dream! I could even imagine other hacks like interfacing a larger amount of flash storage or running a real low end db &scripting engine to have behaviour like mysql/php3 together.

Re:possible to hack cable/adsl routers?

[ls -lR]

My question is why? At the very best, you might be able to implement a very basic web server for static pages but forget about scripting or anything too advanced. It would be dependent on some server in your LAN for storage as well, so you'd still have to run a "real" server anyway. I think you overestimate the amount of processing power in those things. For not much more cost, just get one of those mini-itx boards and install FreeBSD or Linux. You'll get a modern, standards compliant server that can handle nearly any task and it can still be cheap and fanless.

Re:possible to hack cable/adsl routers?

[zakezuke]

So it's a cute idea, probably do-able, but not worth it in practice. You'd be better off going with a cheap bare bones system running Linux or FreeBSD. No CD or floppy drive and underclock it to reduce power consumption.

One thing I know i've discussed over a pint of beer are remote observation stations, trivial little devices that measure temprature, water level, that sorta thing. Out of the way places with NO easy access to landlines.

If you are talking off the shelf barebones system, you are talking a minium of 60watts for basic option. 10watts is a hell of alot more attractive if your power source is something like solar and battery storage.

Re:possible to hack cable/adsl routers?

[grumling]

An intresting solution much like you describe is available already. I have one, and for some aplications such as you describe, it may be just the ticket.

Re:Is the page being served by that modem?

[amcguinn]

What next? RAID-5 using a stack of 8 inch floppies?

Too late

NOT "dual modem" -- rather 1 modem, 2 users

[sonamchauhan]

The "dual modem" mention in the article header made me think for a moment this product allowed multiple users to share a composite link. (See my earlier post on this topic). Rather this product allows 2 users to share *one* link.

A composite link to two *different* ISP could be implemented quite simply by say, using a proxy server to multiplex outbound HTTP requests among multiple interfaces (each interface corresponding to one phone connection).

This approach is more coarse-grained and inefficient than TCP/IP-level channel bonding. However, it would still be useful for places out in the boondocks where you can get two telephone lines, but no broadband. Also, its efficiency could be improved by using HTTP functionality that allows specific byte-ranges to be downloaded for a particular resource.

Who says modem must be used outgoing ?

[gibodean]

Yeah, 56k is pretty slow for lots of us these days.

But, the device is hackable, and so you can turn that modem into an incoming port, instead of connecting to the internet outgoing.

It would be great for me. I've got ADSL, and a non-router modem. I want to share the ADSL between the PCs in my house, and also allow my girlfriend to dial in to use it too (instead of paying an ISP). And, I don't want to have a noisy, power chugging PC running 24/7 just to do that.

This device would be great. One ethernet port to connect to the ADSL modem, one to connect to my internal network, and the landline modem to allow my girlfriend to dial in.

Re:Who says modem must be used outgoing ?

[pe1rxq]

The only downside of your setup is that the 56k modem drops to 33k6 when you use it to dial in...
56k only works if the isp can tap into the digital phone exchange...

Jeroen

Re:xDSL

[FrozenDownload]

Anyone know a good DSL router that runs Linux? We are getting broadband here soon (Woo-hooo!) and I'd love to get one that I could tweak!

i dont know what exactly you mean by "tweak", but many people seem to like linksys, i used to use one myself until i went to a homegrown solution.

The only problem I found with the linksys came after quite a bit of usage, and quite a bit of firmware upgrades, it was the model befsr41, and after a time, if you sent so many packets down the line/sec(i dont even have approx #), it would basically die for a couple minutes before it would come back up. SPI would also not allow for port forwarding. It was however the best router I have worked with before.

I have also helped a couple friends setup some ranging from netgear to dlink to belkin to microsoft. There are a couple quirks with each, like the netgear mr314. If you want to run a server behind that, it doesn't alias the external ip to the lan ports, so basically say you want to ping your external ip,...well you can't. :( you have to refer to it by its internal ip(which would be something to the effect of 192.168.0.1 for netgear).

The microsoft, dlink and belkin i didn't work with quite as much(as far as in depth tweaking), but i assume there are quirks with each of the systems. For the sake of not liking things to be broken as far as functionality, i would recommend a linksys. :)

I differ

[WindBourne]

I bought this the other day to use on networks for remote systems. One of the problems that you run into is being able to access a network when either the internet, the main server, or the firewall machine is out. This is very useful
In addition, I was thinking that this is the perfect device to load a hylafax on. For incoming faxes, I was thinking of using nfs v3 over tcp for the storage.

DirecPC server?

[crypton]

Sounds like this might be usable for anyone wanting to set up a server for a satellite connection that has the downlink via the dish/usb modem and the uplink via ISP/phone modem like DirecPC does. The only linux project so far is at Sourceforge: http://sourceforge.net/projects/direcpc

Dammit, where can I get one?!?!

[Guppy06]

Laugh if you want, but necessity dictates that I can only get a 56k internet connection, and there's two computers in the house. I'm currently using XP's internet connection sharing thingie but I'd kill for a hardware-based solution right about now, at least one that doesn't cost an arm and a leg. I thought Stratitec's (discontinued) "Easy Internet Router," which had a serial port for connecting an external modem as well as ethernet ports, would be The Answer, except that the router seriously slowed down when routing a dial-up connection (tech support's excuse was "Well, we only intended it to be a back-up and the router really isn't designed to do that...")

Now I hear about this, which to me sounds like a Holy Grail, and I can't seem to find it anywhere. The only place I can find it is one of those shady dealers operating on Amazon. There has to be somebody slightly more reputable with some for sale, or at the very least something else to let me compare prices!

Re:Dammit, where can I get one?!?!

[codermotor]

I've been doing this for at least the last five years. I use a 3Com 3C886 56K LAN Modem: 4-port (+1 cross-over) hub, DHCP, NAT, Weblett access, etc.) firewalled by a Netgear FVS318 Firewall/router.

I regularly run at least three PCs on this connection, and have had up to six Internet connections up at a time with no practical loss of speed (seat-of-the-pants benchmarking - the only kind that counts in the real world).

The best part of using one of these rather than a standard modem is the elimination of all that PPP nonsense. The ethernet connection is much easier to setup and manage. Also, I have noticed that with using the LANmodem, I have fewer disconnects than I did with my modem.

The downside to the 3Com product is its cost. I wish the Actiontec had been around when I got my 3Com - it's a third the price. And with a hub or switch, who needs more than one port anyway.

I'm going to be looking into getting one of these for each of my friends and relatives who, like me, cannot yet afford broadband.

Re:Dammit, where can I get one?!?!

[Kazymyr]

Pricegrabber is your friend. Search for "Actiontec dual modem" and you'll find it in several places, the cheapest at Provantage.

Compatability vs. Requirements

[Radical Rad]

They listed the device as compatible with:

Operating System Compatibility Windows 98 / 98SE / ME / 2000 / XP/ MAC OS 7.1 and higher/ Linux / Unix

But then for Minimum System Requirements they ask for:
Windows 98, 98SE, Windows Me, Windows 2000, or Windows XP

Is it necessary to have an ms Windows pc in order to configure the thing? What if all you have is Macintosh or, like me, Linux? Or are they saying that Windows is the bare minimum and, of course, anything else more than meets the requirements?

Re:Compatability vs. Requirements

[Damin]

The short answer is "no, you do not need a Windows PC to configure this thing".

When you plug it in, it defaults to 192.168.0.1 (and 2) and if you setup your PC to pull an address from DHCP, you'll get and address from the box. Then, you can simply http://192.168.0.1 from a Mozilla (or whatever flavor browser you like) and configure it.

They ship this stupid piece of software called "Router Buddy" which has these lame graphics, opens a Web Browser session for you and then adds a Toolbar link to XP so that you can easily connect to the router with a single click.

Samping

[Jennifer E. Elaan]

I was going to mod you up, but I decided to reply instead.

The limitation you refer to has very little to do with managing crosstalk. What actually happened is that the phone company was maximizing the number of channels they could fit on a single wire by using a technology called Frequency Division Multiplexing (FDM).

Since an average voice conversation has a bandwidth of about 2KHz, they built in a low-pass filter with a cutoff somewhere in the vicinity of 3KHz. This means they can heterodyne the channels, each (roughly)3KHz wide, onto a single wire.

Now, this means that the data rate (in terms of zero crossings per second (the original meaning of baud) is limited to about 2400. The "high speed" modems, all the way up to 56K, have a baud rate of 2400. This is a hard limit due to the phone company hardware.

What changed is the number of bits per baud. A 56K modem might use as many as 24 bits per baud, assuming the line is clear enough. The number of bits per baud is capped by the noise floor of the signal, which is also why you won't always connect at 56K (noisier lines can't handle the resolution).

In the move to digital networks, the same total channel datarate was designed into the switching systems. I'm not entirely sure the sampling rate and quantization parameters of these systems, though.