Hey, Ask Slashdot editors: Could we get a slightly higher quality of question and less repetition (we've had the "internet camera" question at least twice).
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I know this may cause thousands of readers to pump up their blood pressure, but if it's a commercial company, then it will naturally target its products on windows (let's face it, if it's a product that needs to make money, windows would be more sensible, not because of the platform's attractiveness, but because that's where the most users are. And this sounds like a home consumer type of product as well.) I can understand it if you want to target BOTH windows and linux, but from your description, it looks like you're sour about moving from exclusively linux to exclusively windows. Why not both?
After all, if it's written in java, that would be one of the key advantages. btw, did you look on computer telephony magazine?
Voice over IP has been a hot subject for quite a while now, but till now we've never seen it being realised on big scale. First I think it has been marketised too much. Voice over ip is not rocket science. For me, it doesn't say more than 'telnet over ip'. Classic telephony calls are practicaly 100% reliable. TCP/IP connections are too unexpectuous: theres a big risk on delays, that are not important for data, but are so for voice. With TCP, you're sure your packets arrives, but it is too slow for voice packets. UDP hasn't this checking, is fast enough, but you are not sure the packets are delivered. How many times we like to see realaudio clips, but that we can't get a connection. Internet telephony is super for applications like netmeeting etc, but when somebody with a real telephone calls another , he expects that his call arrives, not that it is in a jam. People are used to this. So, in my opinion their will not be evolution to internet telephony as long their is no protocol redesign.
Re:The internet isn't made for voice calls.(Score:3, Insightful)
by Th3 D0t ([email protected]) on Monday July 10, @08:56AM EDT
Ever get a "this circuit is busy" message on the phone? IP is more alike to modern telephone networks than you realize. Many (especially long distance) lines are packet switched virtual connections just like TCP/IP. Telephone and IP frequently both rely on packet protocols like X.25 and ATM.
The problem with TCP isn't because it is too slow, but because audio data is temporal. If a router went down somewhere for a few seconds, you don't want hear in fast-forward what the person was saying by the time it gets there. Audio packets have a time dependency after which it just doesn't matter. And as far as UDP, simple retransmission mechanisms are usually built in at the application level to deal with short-term packet loss and reordering.
The only big difference that pertains to your points is that the telephone networks typically have QOS contracts per connection that ensure that each connection will have the required bandwidth and latency needed, whereas internet does not have QOS or priority.
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Re:The internet isn't made for voice calls.(Score:3, Informative)
by softsign (horbal at vlsi dot uwindsor dot ca) on Monday July 10, @08:57AM EDT
(User Info) http://www.vlsi.uwindsor.ca/~horbal/
There is a protocol redesign in the works. That's what Internet2 is being designed for. And I don't mean IPv6.
A lot of the big guns out there are busy developing infrastructure that will allow reliable Voice over IP, real-time video conferencing and other delay-sensitive apps to work reliably.
Cisco's Packet magazine had an article on this a while back (it was the cover story on the last issue). I'm sure there are dozens if not hundreds of other articles on this too.
You will see Voice over IP a lot more in the next few years, simply because it's cheaper to implement than traditional, circuit-switched telephony. It's not a bad thing, really, because the telcos are going to have to make it work 100% of the time. That's the #1 concern. People have been getting dialtones all across this continent for 50 years now. It's simply not acceptable that suddenly you only get 9 out of 10 dialtones. It's got to be 100% or it won't fly.
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Java has a Telephony API, have you looked at that yet. I'm not sure if it is exactly what you want but it is a place to start. Here's a link: http://java.sun.com/products/jtapi/
is a good place to start.
first a Dopple, then a Tripple, then Quadrupel - when will it stop?
I am not trying to be mean, but this is a horrible question. What do you mean by develop "your own technology"? Almost any programming project requires a certain amount of innovation (if its to mean anything, and be sellable by a company).
Secondly, like a previous "ask slashdot", you are confusing the method with the language. This is almost completely dependent on what the employees in your company. The question of whether to use Java is not so much a question of language, but whether you need it to work across platforms. However, keep in mind Java tends to be slow, and usually not such a great thing for realtime involving a lot of data.
If your company decides to use linux, there are many tools available for sound transfer. There are at least 2 or 3 sounds projects I know of. TCP/IP is almost free using any UN*X clone, and that sounds like the majority of your project.
Quicknet has a low - cost 1 port card that will do the trick with Linux and Windows drivers:
Also check out Pika for 4 port cards with traditional analogue and VoIP capabilities with Windows and Linux drivers:
Aslo check out the Bayonne project. Linux based Open Source telephony system with interfaces to Quicknet, Pika, and other cards:
Stephen Nodvin http://www.televid.com
Actually, with a good compression codec (which are quite common), VoIP can take up less bandwidth than a regular analog call. For instance, with CELP compression it's possible to have a full-duplex communication channel in 9600bps (600Bps * 8b/B * 2directions) + protocol overhead (IP + UDP header lengths anyone?) so on a typical 33600bps connection you could likely squeeze 3 simultaneous conversations. IMHO this is why there was a big push in the wireless telco industry to move to digital (what do they really care about call security?).
If you think about it, VoIP is more efficient than your "honest" + "proper voice line".
CELP == Code Excited Linear Predication
I believe it's been around for a while (1970's?).