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DSLBlaster?
The Jake writes: "Here's some mindless link propagation for you, Kuro5hin style. Memepool reports that AuDSL will let you use an old sound card to connect to a subscriber line. "AuDSL is an experimental technology for achieving low-cost leased-line Internet connectivity for homes and small businesses. The acronym AuDSL stands for Audio Digital Subscriber Line. The idea is to replace traditional, expensive leased line modems with software modems running on PCs, connecting the leased line to an ordinary PC sound card. This makes it possible to construct a complete leased line internet gateway entirely from inexpensive commodity PC hardware.""
Somthing similar (and different) was demonstrated by a company recently [and I have owned stock in it for years). http://www.nct-active.com/pr6_5_01.htm
True, though I would think that this is a good thing to have worked on, if only to provide a short-term fix when appropriate hardware isn't readily available. If you need your network connection, but if you can't get a new DSL or leased-line modem for several days, this would be a good thing to try.
And no, I don't think it'd be a good idea to play quake on a machine that's doing this. It's something to be used on a router, IMHO.
I had been curious about this sort of technology a year or so ago, but my math must have been off, and I figured it wouldn't work any better than a standard modem. I'm glad to see that other people had the same idea.
--
You'd save like 20 bucks using a soundcard instead. what the hell's the point of this!?
--
Forget Napster. Why not really break the law?
"Remember when the U.S. had a drug problem, and then we declared a War On Drugs, and now you can't buy drugs anymore?"
From my point of view, the processor is a piece of generalized hardware.
The idea of designing a processor and distributing the design freely has been around for a while. FPGA chips provide a possibility. Check out the OpenCores project. Then there is the Transmeta approach of a very general core processor with surrounding software. Finally, emulators come in and out of vogue.
Pronounced "kuh roh five heen," kuro5hin is a weblog for the l33t. After all, if slashdot was l33t, it'd be named Slashd0t. Kuro5hin did not make a similar mistake by picking something inane like "kuroshin" as its name.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
I've read the damn FAQ. Hell, I spend more time there than here. It's still pronounced "kuh roh five hin," and it's still l33t. More l33t than you anyway.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
So does this mean we'll get a better connection if we use monster cable, just like the guy in the audio store tells us? :)
consult the Jargon Dictionary ... one link is:
_ re incarnation.html
...
http://info.astrian.net/jargon/terms/w/wheel_of
The basic premise is that as CPUs become more powerful, that CPU assumes more of the tasks once relegated to special-purpose hardware. Then, somebody else notices that the CPU is doing "low-value" work, so the tasks move into dedicated silicon
Of course you completely ignored the various compression techniques in use today. Also you are assuming that 48KHZ is a 1 bit mono signal. However soundcards typically have a datarate of 48KHZ * 16-bits * 2 channels = 1.5Mbit / second . That comes pretty close to basic DSL. Taking into account modulation / error correction, that should still leave a sizable amount of IP bandwidth available...
-adnans
"In short: just say NO TO DRUGS, and maybe you won't end up like the Hurd people." --Linus Torvalds
You did something very cool. I love to see other people do stuff like this. Even in a place like Slashdot people can be so negative...
"better ways of doing things eventually just replace the inferior things" - Linus Torvalds 09-08-07
The idea behind DSL was to eliminate the usage of acoustic signals for data transfer. By modulating the DSL signal into an audio stream, you're defeating the purpose.
Sound cards aren't even designed for this sort of thing. The same limitations that hit Winmodems will apply here as well, and will be multiplied. There's going to be some serious CPU usage (which could eventually be partially alleviated by the DSP development) because you still have to modulate/demodulate the DSL signal from audio to data. Not only that, but a specialized circuit must be built to even do this.
I would assume the low cost wouldn't be a factor due to the hassle, and the functionality.
This type of connection will yield slightly-faster-than-Dial-Up speeds at DSL prices. How does that constitute "Low Cost"?
-- Give him Head? Be a Beacon?
-- Give him Head? Be a Beacon? :P)
(If you can't figure out how to E-Mail me, Don't.
Actually, you wouldn't even need to pipe the flourescent light through your optical mouse.
-Waldo
Do you have to use a leased line for this to work? Or could you possibly use this over a standard phone line?
Let's see... A typical stereo sound card has 2 A/D-D/A channels sampling at 44 kHz at 16 bits per sample. So that gives us 44,000*16*2 = 1.4 Mbps. Not too bad I think, but most likely in practice you'll get only a small fraction of this, quite possibly comparable to 128k ISDN or less on the average. A SB16 can only do full duplex with either the A/D running at 16 bits/sample and the D/A running at 8 bits/sample and vice-versa. And one of them will have to be restricted to mono. Which means maximum upload bandwidth will probably be less than a quarter of the download bandwidth, which is not too bad as for the average user, this is made up primarily of HTTP/GET requests :).
Qu'on me donne six lignes écrites de la main du plus honnête homme, j'y trouverai de quoi le faire pendre.
I've always been very skeptical of the claims surrounding the notion of transmitting data at high speed over power lines.
Even if power line data transmission can do all they claim it can (which is doubtful given the reasons you've listed), there is still one fundamental problem to be overcome.
The bandwidth will be shared. If it becomes popular, you're back in the same boat as a cable modem (and to a lesser extent DSL)... a slow connection with high latency.
Bah. If they spent their money on research to make fiber optic lines cheaper to install, they'll be a lot more successful and would make more money.
I mean, why don't they figure out how to trench in a cable more quickly and cheaply? Or how about some radar detection system that would warn you before you dug into a buried power line or water pipe? Or a badger-type robot that digs a hole and drags a cable behind it?
> What about running a network over old soundcards? Possible?
With 100BaseTX NICs being available for $5 - $15, and 100BaseTX hubs being available for $25 - $35, I hardly think it would be practical.
Hey, I already thought of this... sorta. I was thinking that you could hook two computers up over a phone line by using speech synthesis/recognition software. Think how much easier it would be to debug communications issues if you could understand what the computers were saying to each other by eavesdropping...
computer 1: EA BF 02 51
computer 2: Huh?
computer 1: I *said* EA BF 02 51 36
computer 2: Oh, yeah.
Question.. and think about this.. if ordinary modems work over ordinary phones lines why don't high speen modems also work over ordinary phone lines with no new switches??
If you had any signal classes remeber that you have a carrier frequency and an actual signal .. What is the carrier frequency of a modem / phone line and why cannot a modem be made faster? DSL and phones use the same lines so where is the slowdown coming from?
I don't want a lot, I just want it all!
Flame away, I have a hose!
Only 'flamers' flame!
You're not supposed to ask why. Just chuckle and appreciate the Hack Value.
---
As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
Reminds me of an old, crazy idea I had once...which would be to do a bus-topology network using sound cards.
As sound cards don't have some sort of GUID like an ethernet hwaddr, one channel of the stereo sound cable would be used for constantly broadcasting the node's address, and the other used for data.
Was never serious about it, but it was funny to think of...and now someone's actually DOING networking with audio cards!
-- Veni, vidi, dormivi
I think it's good when anyone writes software that is useful for some purpose, even if it's completely proprietary, so I'm not saying that the AuDSL authors have done a bad thing, but I'd like point out that AuDSL is not currently free software, according to the "COPYRIGHT" file in their source distribution:
5. Redistribution of the code as part of, or in association with, a hardware product specifically designed to perform data communications or audio signal signal processing by means of the code is prohibited without the specific prior written permission of Araneus Information Systems Oy.
Also, if you want to go for compatability with the GNU General Public License, the Free Software Foundation claims that these sorts of advertising restrictions are GPL-incompatible (item 3 in the AuDSL COPYRIGHT file).
If AuDSL were freed, I think their encoding implementations might be useful for the various free soft modem efforts, especially with the cheap Computer Telephony Integration risers available on some motherboards that basically connect the built-in AC97 sound hardware to the phone line. I also wonder if the techniques they use to get 96kbps might be usable to provide a "poor man's DSL," although I've heard that some semi-soft modem hardware that includes a Digital Signal Processor is theoretically capable of doing DSL, in which case there might not be anyone who would find this useful and rich enough to afford a premium phone service.
Wonder what would happen if one accidentally piped a BS MP3 through the sound blaster while it was connected to the line? Would the perky umm.. lyrics boost the line speed? :)
It is virtually impossible for ISPs to get inexpensive DSL modems in quantity. The ones that are 50-100 are usually PCI, which ISPs don't want to support. For some reason, the Ethernet ones (bridges and particularly routers) just aren't coming down in price despite their simplicity.
Sure, it's one thing for a tech-head to go on eBay and get a modem for his or her DSL line cheap that may have seen a little use, but an ISP can't get 80 of them to sell to their users that way.
-Chris
...More Powerful than Otto Preminger...
For that matter, why not use ethernet?
I hear they've got ethernet cards which work at gigabit speeds. That's like, 100 megs a second!
Even better, I hear the PCI bus is good for 132 megs a second. Let's just build a PCI to PCI bridge, with 10 miles of telco copper in the middle!
It's digital. It must be better, right?
Nevermind that the telco line won't carry the signal. Nevermind that it wouldn't carry SP/DIF, either. The shit is made for analog signals. It's -good- at carrying analog signals. Thus, analog signals are the order of the day.
Gee, back to the drawing board.
(think first, post later. k?)
Kid-proof tablet..
actually, 16x2channelsx48khz. Closer to 1.5mbit :)
but that's assuming (and usually, with optical ins/outs on good cards) that the card will do it...
Heck, while we're at it, what about some of the higher end cards (96khz? or is it 92? I can't remember)...
Karnal
The idea is to replace traditional, expensive leased line modems with software modems running on PCs, connecting the leased line to an ordinary PC sound card. This makes it possible to construct a complete leased line internet gateway entirely from inexpensive commodity PC hardware.
:)
But you don't understand. If enough traditional, expensive leased line modems are made, then they will become inexpensive commodity PC hardware!
deus does not exist but if he does
This sounds kinda cool, for those that are smart enough to use them. I feel sorry for the people who are gonna have to support it though, anything relying on the average end-users hardware is nuts to support, and anything that is software based (WINMODEMS!!! ACCKK!) is no doubt going to be installed and run on a bunch of p-133s by users who just dont have/want a clue. Then they'll bitch about it. Aside from that its a pretty good idea.
What about running a network over old soundcards? Possible?
.sig wanted: Must be concise, funny, and display my cleverness.
Sure they put DSL in the name, but they operate at 96kbps, or a bit less than twice modem speed wire. My little DSL line is pluggin along at 12 times that rate.
That 96kbps is over a spool of wire. You can not get more than 64kbps through any POTS line that goes through the 8KHz, 8bit conversion in a digital telephone switching system. (If you think you can, then I suggest you find a more lucrative use for breaking the laws of mathematics.)
Further, they make no mention of cross talk sensitivity or generation. Remember that in the US our modems are only 53kbps anyway because of frequency limitations.
I give it an A for inspiration and a D for utility. The FCC will likely give it an F for violating power spectrum limitations on a phone line. (Putting DSL in the name was pure marketing genius! AuModem would never have gotten on slashdot)
Yes yes, I know. Its not funny. But I'm bored so I had to post SOMETHING. :)
-Restil
Play with my webcams and lights here
Not that there are not alternatives to this, but rather there isn't a commodity part they can use to do it.
For Sale: 10 aging "DSL modems" in my closet SoundBlaster brand...
It seems to be market specific. It seems that in some areas, cable modems and DSL modems can be had at the local $BIG_COMP_STORE, but in others, they are strictly handed out by the service provider.
--
"It's tough to be bilingual when you get hit in the head."
You don't use your hands, you use your....
...never mind, it's a guy thing.
- "When I say dance, you'd best DANCE motherf*cker!" -Violent Femmes
8 bits x 8KHz sampling rate = 64Kb/sec
8 bits * 8kHz = 64kHz, not 64kbps.
'bandwidth' is always misused in Comp Sci, it really is measured in Hz (or kHz/mHz), not in bits per second. And 8kHz will not necessarily result in 8kbps (it's not a 1Hz = 1bps relationship).
Soundcards with SP/DIF or Optical I/O are pretty common these days.
Why would you use analog I/O at all?
16bit samples at a 48khz sampling rate= 768Kbps which is pretty respectable.
I gots ta ding a ding dang my dang a long ling long
Look at your units. You're multiplying bits by Hz (which are 1/seconds). That gets you bits/second, which is, incidentally, what bandwidth is.
Perhaps this is why Physics tends to be a required course for Comp Sci majors...
--
Win dain a lotica, en vai tu ri silota
actually last time I was in Compusa they had DSL modems on the shelf ....
Your so damned lucky.
In the uk, for £50, that is probabley about $65 US you can ADSL, and it is capped at 512 down/ 256 up.
And you are contractually forced to use a USB modem, that actually works more stable under windows, than any open Source OS, and is pretty crap under windows.
Who would have thought that ADSL over Windows Dial Up networking was the best way to give your population ADSL?
A Skoda is for life, not for casual humour.
If things are going to be done this way, couldn't they at LEAST use a PCI sound card?
"Everything you know is wrong. (And stupid.)"
"Everything you know is wrong. (And stupid.)"
Moderation Totals: Wrong=2, Stupid=3, Total=5.
Although it is true that some things can be implemented cheaper in software, this is not necessarily true all the time. (And of course cheaper != better)
Is our future generic appliances that can upon downloading the latest software release do whatever we please. Although this would be nice, it is hardly realistic. It flies in the face of years and years of solid task-appropriate engineering.
Furthermore, I don't know anyone who doesn't have DSL because of the price of the damn DSL modem. Its like not having nike's because you can't afford to be replacing the shoe laces.
Software is great for implementing more niche-market type appliances (remember firewalls in the early days.) But the limitations and unnecessary over head of generic solutions will eventually give way to well-engineered solution-specific devices.
I thought winmodems were a thing of the past, but it seems someone is trying to reincarnate them in the DSL flavor. I am sure they will find the limitations of the sound cards a huge-tradeoff for the supposed money savings.
sounds like idea of winmodem taken to extreme:-)
now if somebody would make the sound card work like an ethernet card... etc... just like we have generic CPU we would have a generic input/output device... why bother with all the different hardware solutions?
now excuse me, I have to go to nearest patent office:-)
erik
...all excited, don't know why...
I mean seriously, what they are doing is using their souncard for a tradition modem.
doh!
Sigs are awesome huh?
but
no action:-)
09 F9 11 02 9D 74 E3 5B - D8 41 56 C5 63 56 88 C0 45 5F E1 04 22 CA 29 C4 93 3F 95 05 2B 79 2A B2
The cards were designed for audio - they have filters which remove aliasing artefacts from the output. Sounds better, but it limits the high-frequency response (the filters don't have infinitely sharp cutoff) so the effective dynamic range is less than 16 bits. Also, the Shannon limit is only half the sampling rate, so even without filters you'd "only" be able to get 384 kb/s.
--
So... could I get 6 times the speed using the 5.1 channels in via SPDIF that my SBLive supports?
Better yet, hook up a line to one of the inputs on my stereo. Leave it on as white noise and figure out when the best time to download porn is by how quiet the other traffic is.
Buckets,
pompomtom
Buckets,
pompomtom
"There's an exception to every rule. Except for some rules"
You get much better deals on DSL modems from the usual computer shops
nasty link
In place of my cable modem, I'll hook the cable into my television set. It'll show a scribbly image, but the TV's radiation will minutely interfere with my fluorescent light. By reprogramming the DSP inside my optical mouse and holding it up to the bulb, I'll have a steady stream of data coming through the mouse's USB connector. From there, it's a simple matter of hooking the mouse to my Laserjet's USB port, changing the ROM to redirect the packets out the parallel input port, running that to my Xircom parallel port ethernet adapter, and from there straight into my 10 base-T hub.
Now if I can just think of a way to get from the hub to my computer....
I had an idea once to make a very cheap coordless LAN. It's so simple it's stupid. You just hook up speakers and microphone on all the nodes and cover your ears. Sure you'll get some complaints from the neighbours, and it'll be hell trying to sleep at night while downloading pr0n/MP3s. But it's ultra-cheap and the ancient age of C64 will come back to you!
Too bad it didn't work well because of feedback. LOUD feedback.
- Steeltoe
http://www.debunkingskeptics.com/
Go ahead, moderate this a troll. I can take it.
But seriously, why post this story? It's an utterly useless hardware hack which is tremendously behind the state of the art and (IMHO) doesn't even qualify as particularly creative.
Using audio signals to transmit digital data!! Woohoo!! That's never been done before!! Now, the flourescent light network story was pretty interesting, and at least relatively novel, but this is pure drivel.
If you read the tech specs, they're only getting 96Kb out of this thing, and it requires a leased line. Going through this amount of work to get twice the performance of an ordinary modem seems a bit ludicrous. What I'm amazed about is that they're only getting 96Kb -- I'm no signal expert, but that seems positively anemic given a 48KHz sampling rate. They're only getting two bits per sample?? WTF?? Truly pathetic next to my 1.5Mb DSL at home.
This is news because... why, exactly?
ZFS: because love is never having to say fsck
Actually, it's not. There are major consumer oriented installations of this technology going on in Germany right now, and there are companies that claim to have solved the problem with transformers, surges, ripple control, etc. Broadband down the power line will be feasible for many, many people sooner than you would think; certainly years before this sound card idea...
As it says at their site, it is currently only able to reach speeds of 96 kbps. Why not use a modem instead?
Other things worth noting: "Running on a 333 MHz AMD K6-2 processor, the software modem consumes about 38% of the CPU cycles." - Ouch. And that's on Linux. I wouldn't want to try something of the sort on Windoze with a few browser windows and an app or two open.
Could this technology become interesting? Perhaps... maybe in three years when they have the bugs worked out and the code optimized, you can use it to get 256 kbps, maybe... Personally, I'm not planning on waiting that long!
There are so many better solutions out there, and if you want my opinion, the real future of broadband is in the wire that is already running into your house. No, not the phone wire. This one. Now serving over 90% of the world's population...
Im sure your proud you didnt need a another parent, but if we asked your kid I bet they would vote differnt. Maybe the wouldnt choose the person you decided to get drunk with that one night, but Im sure they have a mental picture of the person other person they would like to be related to. If they dont Im sorry you warped your kid that much. The only good thing is that your warped kid will have trouble having kids as well, and well we know where that goes, you loose, darwin wins ^H^H^H^H^H^H We win.
You can raise a kid with one parent but it shouldnt be done
You can drive a car with your feet but it shouldnt be done
You can fertalize you lawn with used motor oil but it shouldnt be done
And now you can build a DSL modem out of a soundcard but it shouldnt be done
Shannon had a couple of good theorems, but the one you're talking about is courtesy of Nyquist. To have any chance of recovering sampled data, the sampling rate must be at least twice the highest frequency content of the original, analog signal. The original poster's calculation (16 bits/sample * 48 ksamples/sec) was right, but it assumes a noiseless channel.
Shannon's noisy channel theorem is probably more applicable. (the heorem's result is likely what he meant by "Shannon's limit.") Shannon said that a channel's capacity in bps equals channel bandwidth(Hz) * log2(SNR+1). A classic example is the plain old telephone system. The bandwidth allowed is about 3kHz (300Hz - 3.3kHz). The SNR the telcos try to maintain is around 35db, or about 3100. This gives a maximum reliable capacity of around 35kbps.
One fun side note: the 3khz bandwidth limit is not an inherant limitation of the copper telephone lines. It's actually the frequency range chosen as sufficient for voice communication by none other than Alexander Graham Bell. His original equipment used this 3khz bandwidth, and all subsequent telephone equipment adhered to the same standard. Though it was made more than 150 years ago, his choice for bandwidth stuck (and is the reason many of us *still* can't get DSL connections to our homes!).
A couple of Speakers and mics, and you could have a cheap wireless network!(though, the noise may drive you a little nuts).
They ought to be able to do much better given a solid copper pair, 16-bit D/A and A/D, and a 48KHz sampling rate. The Shannon limit for that setup is 48000*16 bits/sec, or 768 Kb/s. That's under optimal conditions, but ordinary modems routinely get 80% of the Shannon limit for their medium (8 bits x 8KHz sampling rate = 64Kb/sec) The line has to be characterized during startup and appropriate equalization applied, but that's a well-understood process built into every modem.
How do they connect .?
-=[the machine masters the grim and the dumb]=-
You know, I was just thinking...whatever happened to the days when geeks would look at something like this, useful or otherwise, and say "cool!"
I suggest people better understand the sources for others frustration before being so quick and naive to judge.
also amusing is that the moderater didn't even leave a comment as to why. Interesting that on Kuro5hin, one is held accountable for their actions.
In NZ, we can subscribe to bandwidth choked flat-rate DSL. The only preventative measure is the modem cost (which is significant compared to the relatively small benefit of the crippled-DSL service). However, for people with the modems already, it's great. Now, if I can plug my box into my DSL line through my soundcard (sitting dormant in the case), I'm very happy.
Sure, this won't stop most people from going the whole DSL hog, but it's a damn fine hack that shows geek ingenuity at it's best.
--
Tarkwyn.
He died on July 6th, not June 6th.
Oh, and you were 30 years too late, AC.Sounds like a good idea but I hope they do a better job than the software modems/printers (WinModems...) that we all think are terrible. But would it tie up my sound card? What good is DSL if I can't listen to the MP3s I download?
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
If it weren't June, I'd take it for an Aprils Fool, but at a cursory glance it does look like the guy actually built it. It would be cool in areas where copper is available, but ADSL gear is out because of the distances.
Bert Driehuis -- All I asked was a friggin' rotatin' chair. Throw me a bone here, people.
Can you go to a clue store and buy one? Please? Stop whining. The chances are, you won't ever use this or see it in use. The main points are a) the hack value and b) your friend's a retard. It doesn't take a genius to setup an ethernet connection. It's one thing not to be able to set one up, thats perfectly fine. But to say someone who is "very capable in setting up and tweaking his DSL setup" obviously does not refer to one's knowledge of an operating system.
"Nature doesn't care how smart you are. You can still be wrong." - Richard Feynman
My athlon doubles as an electric burner. . .
WhiteWolf666 an exBush supporter. All you new-school,compassionate,save the children Republicans can rot in hell
ADSL modems (at least; don't know about SDSL) aren't actually that expensive. They can be had (used) for $50-$100 if you do a little looking. They're aren't very complicated devices. The reason they cost alot is that the manufacturers currently are only supposed to sell to DSL providers: the end user can't just pick one up at CompukeSA, so the providers charge what they want.
So what I don't understand is, why would the providers ever go for something like this?
Oh yeah, and don't even think about netgaming on this system. Soundblasters have a bad habit of taking over the PCI bus as it is. I can't imagine this making it anything but worse.
"Research is what I am doing when I don't know what I am doing." -- Wernher von Braun
Why can't you use wireless ethernet?
If it ain't broke, it doesn't have enough features yet.
A DSL line gets its speed mostly by virtue of not having to fit the bits through a 4khz filter. Shannon tells us that 33.6 is about the limit for a 4kz signal - 56K modems actually cheat (hint - *every* computer store stocks the "consumer" end of a 56K modem - ever tried to buy the *uplink* end of the pair, and provisioned the line from the telco? ;) Also, there's no pesky power restrictions - those enter into it because the power determines just how close to a perfect square wave youy can get (since the power is basically the slope of the near-vertical parts of the waveform).
Just what we need, another round of WinModems. DSL is hard enough to get working in Linux. My friend, who is very capable in setting up and tweaking his DSL setup, spent three months of trial and error getting his DSL connection working with Linux. The last thing we need is a software modem to make it even worse.
A while back, I attempted to scrape together a wireless ethernet connection of SOME type out of some modems and a couple of cheap-O walkie Talkies...
Needless to say, it was a TOTAL flop. The walkie talkie transfer was garbled beyond recognition and I couldn't even connect the two points at 300bps. (I seriously have to question whether it would have worked at all to start with though- I'm not a genius with funky software hacks, but I know enough to hang myself with...)
The POINT was to build a better way to transfer MP3's to the hard drive in my car's mp3 player--yah- one more keen ornamental hack, but it would be much nicer to do it that way than physically either lug the whole unit in or string a frikkin LONG cable all the way out to the garage...
So I'm thinking this sound based hack PLUS a couple of those high tech mini-fm 2 way radios that seem to be everywhere now, and this just might work!
Anyone else been down this road?
Sig currently under construction. Mind the gap....
No kidding. You forgot noise.
Just because you slap 16 bit D/A/D gear on the ends of the wire doesn't mean you're going to get 16 bits per symbol through it, sweetie. Hell, why not use 32 bits? 128? The sky's the limit!
Shannon also says that you have to divide in the noise level to figure out how many bits you can get per symbol. THEN you design your D/A/D gear to suit. Dialup PC analog phone modems use 2400 symbols per sec x 14 bits per symbol for 33.6 kbps -- 2400 Hz because of the phone system audio sampling rate and 14 bits/symbols because of the expected noise floor and maximum allowed signal power (FCC limit). 56 kbps cheats the noise floor down a bit but I won't go into that.
Now, *IF* you've got a LEASED LINE that you can dump massive signal power onto (i.e. no other equipment on line), and you've got low inter-symbol interference (ISI - think of it as a time smear of the symbols), then hell yeah you can get 768 kbps. And I'd drive 130 MPH to work if it wasn't for those pesky cops (and curves).
One simple rule for its versus it's
When will they tell me I can use my PC speaker for a T1?
When death looks you in the eye, smile. Someone needs to cheer him up.
I wonder what speeds could be achieved over a radio link. I have a few good friends that are hams, and we are always complaining about the fact that we are 20 miles apart without line of sight, which rules out the possibility of a high speed link. We talk over voice links all the time, but the fastest we can get without line of sight with of the shelf hardware is 9600 baud(38400 if we could get ahold of some data radios). The problem is that for each packet the transmitter has to be keyed up, sends a preamble, then sends a IP packet wrapped in a fake AX25 header. Sure, these are the links that TCP/IP was designed for, but we have come along way since then. The only time I have seen people play Q3 over ham radio(A wonderful use of our spectrum) was over microwave links. I know 56k/78k equipment does exist, but I don't feel like shelling out 800 bucks at each end for those speeds.
- get both channels working,
- run them on two different lines to two different computers,
- get the TCP/IP stack integrated.
I wonder if a person could use a sound card to interface to POTS? That way they could use their PC to figure out whether to make a local call using the phone company or make a long distance call using an Internet phone gateway and still be able to have a phone number that people can call.
science is a religion
I'm guessing no. But to answer your question: yes.
--
Where does Kuro5hin.org get its name? (Go To Top) No, it is most decidedly not 'l337. It is a pun on Rusty's name. Kuro5hin == corrosion == rust == rusty.
look here---> Kuro5hin origin
Don't eat shrimp candy, just a heads up.
Here's the problem: The switches are digital. "Digital Quality" isnt always good - "Digital Quality" in phone terms is 8kHz 8bit. Also, phone lines (in general) cant go any higher than 4kHz frequencies - from load coils to keep lines from having too much capicatance. Load coils also kill DSL - DSL is above the 4kHz band limit - but you put the filters in your OWN house instead of on the lines on the poles.
My theory is that they are so snowed in for most of the year they sit in front of PC's and code. This is just cool.
--
Jon - TheSpork
This will not interfere with phone signal. Anyway, it looks like this will work on dedicated copper pairs, not on regular phone lines.
If they could get decent bandwidth out of it, I mean, where I am, DSL is $80 a month and it's available in only one small part of town. Oh yeah, and i would have the modem already =)
Most soundcards can digitize sound at 48kHz.
That's about 48k signals per second.
For a byte, you need 8 signals.
That's now 6kB/s. Not really a DSL killer.
Don't answer me. Moderate. Slashdot is about moderation, not discussion.
as the website states, you can link up two pc using soundblasters, and even old ones. So, it can be a great emergency toolkit to carry around (instead of pcmcia ethernet, or null modem/printer cables). Better than a regular modem (max speed 115200bps), you can use it -for example- to link together old laptops with only one pcmcia and one floppy and no cdrom reader to install linux/bsd :)
-- There are two kind of sysadmins: Paranoids and Losers. (adapted from D. Bach)
. . .but I'm not entirely convinced of it's feasability.
Let me explain.
Using audio to transfer data isn't a new idea. The humble telephone line modem bears witness to that, as does modern DSL.
What is new about this is the really creative hardware hack. Sound cards (like any other expansion card) are manufactured with a purpose in mind (in this case, that purpose is producing or inputting sound). With the exception of some cards produced with a modem input, these adapters may not be designed in such a way to enable data transfer.
That would have to be addressed in software. To make this method widely-used, AuDSL would need to include modified drivers for common sound cards in addition to the software instructions that tell your computer how to take this audio data and turn it into something usable.
And then there's the matter of it taking 38% of CPU cycles. . .
A better solution might be to design a less expensive alternative to already existing hardware that would work with already existing systems.
I admire their ingenuity, but I wonder if there isn't a better way. . .
yes, tech support? i'm having a problem with your product. my phone jack isn't fitting into the sound card correctly.
;)
thank you all for just recreating the age old problem of fitting a square peg in a round hole
**AA: a bunch of mindless jerks who'll be the first against the wall when the revolution comes
So maybe I can hook up some really big ass speakers to my soundblaster DSL and use the microphone input on my laptop and become my own wireless ISP. It might annoy the neighbors...oh well.
New technology was recently unveiled that allows one to use their video card as an in-home neutron accelerator.
Try cancelling one of the thirty eight Napster downloads you are running..
44.1 kb/s per DSP channel (voice) * 16 voices (your basic old soundblaster) equals 705.6kb/s SW33T!
Of course he doesn't live in Maine. He's dead ;)
~Mike
~Mike
~Mike
A big enough hammer fixes *anything*
i have a ac'97 codec on my motherboard. some of us can't afford pci sound cards. but the nvidia mcp chipset does look nice
Using nonstandard line modulation might make it more difficult for a third party to sniff data from off the wire. Maybe it's even possible to measure if the line has been compromised.
The main difference (as I read the site) is that your modem is in software rather than hardware. How about working up an 1/8" audio to rj-11 adaptor and just pretend it's a modem?
What's tty3 and why won't my program exit when I push Alt-F4?
-- MarkusQ (aka MQR)
So all we need to do is encourage this trend until we get to the point where someone figures out a way to simulate the processor with software and Presto! computers cost nothing to replicate, generate no heat, and can be shared over Napster.
-- MarkusQ
Next week: How to legally avoid paying taxes without having to earn any money.
While I do not know what it is, it is mentioned and the posting so I guess my question is relevant. What is a kuro5hin?
"There ought to be limits to freedom"
Verison can't find their collective arse with both hands and one of mine! As long as I'm restricted to their lines it doesn't matter if I can hook up 5000 with free massages of [insert favorite appendage here] while I surf the Internet. But it does sound trick...too bad.
In this case, software emulation and stock hardware makes more sense for ham radio, where you otherwise end up purchasing an expensive, specialized modem anyway, and you certainly don't expect speeds like 768kbps from radio (most amateur packet radio is still 1200 baud)
This is a great candidate for some graduate student's research project, but a really hard sell for some poor marketing department.
--
There is no hatred more pure and true than that expressed by children.
It is now two years since I developed AuDSL. At that time, DSL modems were not cheap, and DSL was not being offered as a commercial service to residential users, at least not in Finland where the AuDSL work was done. With local phone calls being billed per minute, the options for people wanting an always-on connection in their home were very limited.
Some people were leasing raw copper pairs to nearby ISPs or employers willing to provide connectivity, and buying routers and rather expensive synchronous leased line modems with v.35 interfaces or (as I did) 38.4 kbps four-wire baseband modems. In that context, AuDSL actually had some utility, but mostly I built it out of curiosity to see whether it could be done and for the sheer hack value of it. It has never been the intent for AuDSL to become a mainstream technology or the basis of a commercial service.
I can pipe the network traffic to my speakers, at a sufficient volume, have a mic pick up God's voice in another rooom, and reconstitute the packets. Hey, it's wireless...pretty useless, but neat!
Sounds good economically. However, what will it do from a speed and reliability standpoint?
Death is only the beginning...