Re: Voice over GPRS?
On Sat, 3 Feb 2007, Ian Stirling wrote: > Even a really anemic processor can manage AES or whatever at 8Kbit/sec, in > realtime. > However, as a near-zero CPU option, you could always use one-time-pads from > the SD. > Key management is substantially more annoying - you need 3M or so of pad per > person per hour, and you can't reuse it. > However, as long as nobody copies the pad, or compromises the phone, it's > perfectly secure, even from advances in decryption. > Overwrite the flash several times as the pad is read, and then take out and > crunch the SD between your teeth if you need to destroy it. The pad can be stolen from both ends, and you'd have no perfect forward secrecy. Using a onetime pad directly is inheritantly dangerous. You are better of using the one-time pad to authenticate a diffie-hellman key exchange, and then use session keys which are never stored to flash, written to disk, and can be safely intercepted. And that's all provided your onetime pad is truly random, which it won't be, and that people won't accidentally use the same page twice. Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
Crane, Matthew wrote: With a point to point link what would be the minimal software stack needed? There's only so much CPU, might it be more appropriate to use a relatively lightweight process to rx/tx+encrypt/decrypt the data? In any case, the idea of an open encryption standard for cell phone communications is pretty appealing. Even a really anemic processor can manage AES or whatever at 8Kbit/sec, in realtime. However, as a near-zero CPU option, you could always use one-time-pads from the SD. Key management is substantially more annoying - you need 3M or so of pad per person per hour, and you can't reuse it. However, as long as nobody copies the pad, or compromises the phone, it's perfectly secure, even from advances in decryption. Overwrite the flash several times as the pad is read, and then take out and crunch the SD between your teeth if you need to destroy it. (Your Dental Bill May Vary) ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
pe, 2007-02-02 kello 20:51 +0100, Paul Wouters kirjoitti: > On Fri, 2 Feb 2007, Mikko Rauhala wrote: > > Righto, so somebody's doing it already on free software. Good for us > > all :) > > cryptophone's phone cost 1500 euro. It's not free software. The source has > been published for peer review, but you're not allowed to use it on your own > phone. Righto, I mixed it up on the text on your other url. -- Mikko Rauhala - [EMAIL PROTECTED] - http://www.iki.fi/mjr/> Transhumanist - WTA member - http://www.transhumanism.org/> Singularitarian - SIAI supporter - http://www.singinst.org/> ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On Fri, 2 Feb 2007, Mikko Rauhala wrote: > > > Of course, you can make a GSM data call (I presume) and thus reserve > > > > That's what www.cryptophone.de does to avoid latency issues. Some networks > > block mobile to mobile data calls though. > > Righto, so somebody's doing it already on free software. Good for us > all :) cryptophone's phone cost 1500 euro. It's not free software. The source has been published for peer review, but you're not allowed to use it on your own phone. > I was referring to simply that the carrier will likely charge extra for > data calls (in comparison to voice calls). Though now that I check the > figures, they _have_ come down at least here since last I checked. Which > was a while ago. Well, most offer a $100/month or so flatrate. It's expensive, but if all your calls are going through a cheap SIP provider and your asterisk to your GPRS connection, your *voice* calls would go down to $0/month. Then, $100 for unlimited voice calls isnt that expensive. Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: What more to add to http://www.linuxtogo.org/gowiki/OpenMoko/GPRS ? Re: Voice over GPRS?
pe, 2007-02-02 kello 19:14 +0100, Robert Michel kirjoitti: > BTW do you think two low quality phone connecitons would be possible > via 9600 Baud? Pushing it, but if you don't run it over IP and rather have the same software on both ends of the data link and therefore cut out all but the most simple (custom) multiplexing overhead, maybe you could hack it using minimal Speex. -- Mikko Rauhala - [EMAIL PROTECTED] - http://www.iki.fi/mjr/> Transhumanist - WTA member - http://www.transhumanism.org/> Singularitarian - SIAI supporter - http://www.singinst.org/> ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
pe, 2007-02-02 kello 18:28 +0100, Paul Wouters kirjoitti: > On Fri, 2 Feb 2007, Mikko J Rauhala wrote: > > > Of course, you can make a GSM data call (I presume) and thus reserve > > That's what www.cryptophone.de does to avoid latency issues. Some networks > block mobile to mobile data calls though. Righto, so somebody's doing it already on free software. Good for us all :) > > (Also, _this_ is how you can accomplish a proper encrypted phone call > > using the GSM network with Neo, if you're into security and don't mind > > it costing a bit. > > It doesnt need to cost a bit. I was referring to simply that the carrier will likely charge extra for data calls (in comparison to voice calls). Though now that I check the figures, they _have_ come down at least here since last I checked. Which was a while ago. My particular provider does still seem to charge sizable extra for receiving a data call, though not for making one, leastways a 9k6 one. (Which immediately springs into mind that one needs to support nudging a phone to come online and connect with the secure VOIP service using a single-ring call from a known caller ID. This would save on data call reception charges and the particular signaling method would be free too... Didn't yet check to see if you already support something like this :) -- Mikko Rauhala - [EMAIL PROTECTED] - http://www.iki.fi/mjr/> Transhumanist - WTA member - http://www.transhumanism.org/> Singularitarian - SIAI supporter - http://www.singinst.org/> ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
What more to add to http://www.linuxtogo.org/gowiki/OpenMoko/GPRS ? Re: Voice over GPRS?
Salve Paul! Paul Wouters schrieb am Freitag, den 02. Februar 2007 um 18:13h: > On Fri, 2 Feb 2007, Robert Michel wrote: > > > Does anybody has experiances/ideas about Voice over GPRS? > > See: http://www.cl.cam.ac.uk/~rc277/globe02.pdf Thank you, I direcly put this good source into our wiki :) Sorry for switching now to GPRS general: For the GPRS connection in general would be more interesting: - firewall on the Neo - what is with GPRS push services? - how to count the GPRS traffic (to count equal to the provider) - a limitation of data/hour data/day data/week data/month with user warning - statistic for GPRS traffic use - for prepaid cards automaticaly checking the prepaid credit/money on account -- before and after calls -- each day/hour or each 10MB GPRS traffic And just an idea in case that the Neo has only GPRS class B: Using another old GSM mobil with GPRS and Bluetooth - so using Internet connection while phonig whith the help of the second phone. BTW do you think two low quality phone connecitons would be possible via 9600 Baud? Greetings rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: between 300ms and 10s - wow that is asyncron :) Re: Voice over GPRS?
* Robert Michel <[EMAIL PROTECTED]> [070202 18:58]: > Salve Andreas! > > Andreas Kostyrka schrieb am Freitag, den 02. Februar 2007 um 18:44h: > > Looks nice, BUT you don't have always a 14400 bps uplink. > But even iax2 has a huge overhead - mybe still potential to > optimize the protocol? > > > > So my question would be how much delay will bring a GPRS > > > connection compared with normal internet connections? > > > > Somewhere between 300ms and 10 seconds. (I think I once that over > > 60seconds ping times in Munich ;) ) > wow - so for browsing a proxy could become interesting to > preload the next newspages... The problem is that with GPRS you don't have that much bandwidth to do background fetches :( (EGPRS/EDGE would be a different thing) Plus people pay for these bandwidths in most places on this planet :( Plus, the 10secs was a maximum value that I've encountered multiple times. With GPRS the latency most often sticks below the 2secs bracket, but 10secs do happen from time to time. UMTS is, IMHE, worse :( Andreas ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
between 300ms and 10s - wow that is asyncron :) Re: Voice over GPRS?
Salve Andreas! Andreas Kostyrka schrieb am Freitag, den 02. Februar 2007 um 18:44h: > Looks nice, BUT you don't have always a 14400 bps uplink. But even iax2 has a huge overhead - mybe still potential to optimize the protocol? > > So my question would be how much delay will bring a GPRS > > connection compared with normal internet connections? > > Somewhere between 300ms and 10 seconds. (I think I once that over > 60seconds ping times in Munich ;) ) wow - so for browsing a proxy could become interesting to preload the next newspages... Thank you for you feedback, rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
RE: Voice over GPRS?
With a point to point link what would be the minimal software stack needed? There's only so much CPU, might it be more appropriate to use a relatively lightweight process to rx/tx+encrypt/decrypt the data? In any case, the idea of an open encryption standard for cell phone communications is pretty appealing. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Paul Wouters Sent: Friday, February 02, 2007 12:29 PM To: Mikko J Rauhala Cc: community@lists.openmoko.org Subject: Re: Voice over GPRS? On Fri, 2 Feb 2007, Mikko J Rauhala wrote: > Of course, you can make a GSM data call (I presume) and thus reserve That's what www.cryptophone.de does to avoid latency issues. Some networks block mobile to mobile data calls though. > (Also, _this_ is how you can accomplish a proper encrypted phone call > using the GSM network with Neo, if you're into security and don't mind > it costing a bit. It doesnt need to cost a bit. In fact, this is why I am on this list and why I'll be getting a Neo phone. We presented at CCC: http://events.ccc.de/congress/2006/Fahrplan/events/1495.en.html The video is available at: http://chameleon.cypherpunks.ca/ In essence, a phone using Openswan, Xl2tpd, openvpn, pjsua, Jabberclient talking to an server running Openswan, Xl2tpd, openvpn, asterisk, jabber server. We hope to have Neo firmware available before you can order the hardware :) For more details, see our presentation. Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
* Robert Michel <[EMAIL PROTECTED]> [070202 18:26]: > Incoming bandwidth: 14.5 Kbps > 0.01 Mbps > 1.81 KBps > 0 MBps > > Outgoing bandwidth: 14.5 Kibps > 0.01 Mbps > 1.81 KBps > 0 MBps > Total bandwidth (incoming and outgoing): 29 Kbps > 0.03 Mbps > 3.63 KBps > 0 MBps > > 29Kbps = 3.625 kByte/s Looks nice, BUT you don't have always a 14400 bps uplink. Beside streaming VoIP without QoS can only work with an strong oversupply of bandwidth. In the case of GPRS you often have only 9600-14400 bps uplink spped. > I was not speaking about VoIP, I was talking about > asyncron voice services like the buzzthingy > "Push to talk" - but I do not whant to push - > "Talk to talk" would be more smart - no need to > press a button. That seems reasonable. > So my question would be how much delay will bring a GPRS > connection compared with normal internet connections? Somewhere between 300ms and 10 seconds. (I think I once that over 60seconds ping times in Munich ;) ) Andreas ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On Fri, 2 Feb 2007, Andreas Kostyrka wrote: > > AFAIK, only T-Mobile did that, and they removed that clause a few months > > ago. > > Eplus does have that clause too. Ahh, not too familiar with the German markets. > Plus running standard VoIP protocols like SIP and friends over a NAT > firewall that is not cooperating is not possible anyway. So you would > need to add a tunnel to some endpoint on the Internet, and add that > latency to the bad latency of GPRS/UMTS :( that's why our firmware will include both IPsec (with NAT-Traversal) as well as OpenVPN. If that wouldn't work often enough, we'll try and do encapsulation over port 443. But yes, guaranteed in-order delivery of telco networks is really not a very nice basis to run UDP (or TCP) over. Guess the telco world still believes in the OSI model :( Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Ok I should write _asyncrone_ Voice over GPRS in the subject from the beginning ... ; )
Salve Andreas! On Fri, 02 Feb 2007, Andreas Kostyrka wrote: > * Paul Wouters <[EMAIL PROTECTED]> [070202 18:18]: > > On Fri, 2 Feb 2007, Terrence Barr - Evangelist, Java Mobile & Embedded > > wrote: > > > Also, most data plans specifically prohibit VoIP usage > > > and may even prevent it technically. > > > > AFAIK, only T-Mobile did that, and they removed that clause a few months > > ago. > > Eplus does have that clause too. Who cares? When the communication is asyncron we could store the voice date in one file that even is encrypted... .. when we talking about asycrone Voice over GPRS - voice chat with a little delay... Cheers, rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
Salve Terrence,*! Terrence Barr - Evangelist, Java Mobile & Embedded schrieb am Freitag, den 02. Februar 2007 um 17:52h: > VoIP calls typically require approx. 120 kbit/s *each* > direction, that's 240 kbit/s for a two-way conversation. http://www.asteriskguru.com/tools/bandwidth_calculator.php [*] speex [*] iax2 Incoming Bandwidth Calls: 1 RTP: 4.69 Kbps UDP: 3.13 Kbps IP: 7.81 Kibps Protocol: IAX2 REGULAR Audio Codec: 2 Kbps *IAX2 REGULAR is not using RTP or RTCP! Outgoing Bandwidth Calls: 1 RTP: 4.69 Kbps UDP: 3.13 Kbps IP: 7.81 Kibps Protocol: IAX2 REGULAR Audio Codec: 2 Kbps *IAX2 REGULAR is not using RTP or RTCP! Incoming bandwidth: 14.5 Kbps 0.01 Mbps 1.81 KBps 0 MBps Outgoing bandwidth: 14.5 Kibps 0.01 Mbps 1.81 KBps 0 MBps Total bandwidth (incoming and outgoing): 29 Kbps 0.03 Mbps 3.63 KBps 0 MBps 29Kbps = 3.625 kByte/s VoIP over cellular is just not feasible at this point. I was not speaking about VoIP, I was talking about asyncron voice services like the buzzthingy "Push to talk" - but I do not whant to push - "Talk to talk" would be more smart - no need to press a button. Without syncron communication the overhead would be lower > >On 2/2/07, Robert Michel <[EMAIL PROTECTED]> wrote: > >>Salve! > >> > >>Does anybody has experiances/ideas about Voice over GPRS? > >>How long is the delay? It could maybe used for asyncron > >>voice communication Talk2Talk (instead of pushing a button) > >> > >>In Germany did three Prepaid Provider published new Tariffs > >>with 0.24Euro/MB. > >>German pages: > >>http://teltarif.de/arch/2007/kw05/s24754.html > >>data cost calculator: > >>http://teltarif.de/mobilfunk/datenrechner.html > >> > >>I think with this tariffs using mobil data becomes > >>interesting ;) > >> > >>By using 1KB/s for audio and some overhead, let > >>us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, > >>60 seconds makes then about 3 cents. When both using > >>this 6 cents. Hmm that would be interesting when > >>the user makes often make brakes/pause in their talk. Sorry guys, I was not asking about codecs, I was just asking about delay on GPRS. ;) Should I start again with a more simple example? I will send a voicemessage of 20 seconds to my friend. My Tarrif would cost with 60/1 second counting full 16 Cent. 20 second audio with 2.150 kbit/s will create a file of 43 kbit = 5.375 kByte. 0.24Euro/MByte GPRS traffic with 10KB block will calculate 10 kByte for the message to my frind, this makes 0.0024 Euro = 0.24 Cent for me. So my question would be how much delay will bring a GPRS connection compared with normal internet connections? Greetings, rob Greetings, rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On Fri, 2 Feb 2007, Mikko J Rauhala wrote: > Of course, you can make a GSM data call (I presume) and thus reserve That's what www.cryptophone.de does to avoid latency issues. Some networks block mobile to mobile data calls though. > (Also, _this_ is how you can accomplish a proper encrypted phone call > using the GSM network with Neo, if you're into security and don't mind > it costing a bit. It doesnt need to cost a bit. In fact, this is why I am on this list and why I'll be getting a Neo phone. We presented at CCC: http://events.ccc.de/congress/2006/Fahrplan/events/1495.en.html The video is available at: http://chameleon.cypherpunks.ca/ In essence, a phone using Openswan, Xl2tpd, openvpn, pjsua, Jabberclient talking to an server running Openswan, Xl2tpd, openvpn, asterisk, jabber server. We hope to have Neo firmware available before you can order the hardware :) For more details, see our presentation. Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
* Paul Wouters <[EMAIL PROTECTED]> [070202 18:16]: > On Fri, 2 Feb 2007, Robert Michel wrote: > > > Does anybody has experiances/ideas about Voice over GPRS? > > See: http://www.cl.cam.ac.uk/~rc277/globe02.pdf > > They discuss tcp as well as udp performance over GPRS. > > > How long is the delay? It could maybe used for asyncron > > voice communication Talk2Talk (instead of pushing a button) > > > By using 1KB/s for audio and some overhead, let > > us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, > > 60 seconds makes then about 3 cents. When both using > > this 6 cents. Hmm that would be interesting when > > the user makes often make brakes/pause in their talk. > > Using speex, you'd need 1.6kb upstream. So bandwidth is not the GPRS often has only 9600 bits per second, aka 1200 bytes per second upstream at best. Andreas ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
* Paul Wouters <[EMAIL PROTECTED]> [070202 18:18]: > On Fri, 2 Feb 2007, Terrence Barr - Evangelist, Java Mobile & Embedded wrote: > > > Also, most data plans specifically prohibit VoIP usage > > and may even prevent it technically. > > AFAIK, only T-Mobile did that, and they removed that clause a few months ago. Eplus does have that clause too. Plus running standard VoIP protocols like SIP and friends over a NAT firewall that is not cooperating is not possible anyway. So you would need to add a tunnel to some endpoint on the Internet, and add that latency to the bad latency of GPRS/UMTS :( Andreas ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On Fri, 2 Feb 2007, Terrence Barr - Evangelist, Java Mobile & Embedded wrote: > Also, most data plans specifically prohibit VoIP usage > and may even prevent it technically. AFAIK, only T-Mobile did that, and they removed that clause a few months ago. Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On Fri, 2 Feb 2007, Robert Michel wrote: > Does anybody has experiances/ideas about Voice over GPRS? See: http://www.cl.cam.ac.uk/~rc277/globe02.pdf They discuss tcp as well as udp performance over GPRS. > How long is the delay? It could maybe used for asyncron > voice communication Talk2Talk (instead of pushing a button) > By using 1KB/s for audio and some overhead, let > us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, > 60 seconds makes then about 3 cents. When both using > this 6 cents. Hmm that would be interesting when > the user makes often make brakes/pause in their talk. Using speex, you'd need 1.6kb upstream. So bandwidth is not the issue. Latency is. The uplink will have between 0-1 sec of latency, so it's not really an issue . Downlink however, commonly has 2 or 3 second latency, ruining voice in an "interactive" way. In other words, you are probably forced to use a "push to talk" style conversation, meaning long monologues. And that is in good conditions, with a non-mobile connection. Things will get much worse when travelling, especially in the city with many small cells, as you'll be stuck hopping from cell to cell without actually getting much communication done. Paul ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On pe, 2007-02-02 at 11:37 -0500, ROB wrote: > 1kb/s isn't going to get you too much audio. Try encoding an mp3 at > 1kb/s to see how audible that would be. I think you'd be looking at > something more along the lines of 32-64kb/s to get anything that you > could understand. mp3 isn't designed for that, though even speex's minimum is 2kb/s (probably you want to use more). Anyway, Robert was talking about 1kB/s, which is quite fine already. But the main point that GPRS is not for VOIP really stands; short voice messages, sure, an ongoing dialogue, no. Of course, you can make a GSM data call (I presume) and thus reserve bandwidth from the network; some latency issues would remain, but you could probably get a reasonable VOIP connection going on that with low-bandwidth Speex; would likely cost you but perhaps be an affordable option for intl. calls. (Also, _this_ is how you can accomplish a proper encrypted phone call using the GSM network with Neo, if you're into security and don't mind it costing a bit. Doubleplusgood if you can make a data call from cell to cell direct without both sides having to initiate their own data calls; not sure about that, GPRS suffices for my uses so haven't looked at data call capabilities.) -- Mikko J Rauhala <[EMAIL PROTECTED]> University of Helsinki ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
On Fri, Feb 02, 2007 at 11:37:59AM -0500, ROB wrote: > Bit rate=sampling rate x bit depth > > 1kb/s isn't going to get you too much audio. Try encoding an mp3 at > 1kb/s to see how audible that would be. I think you'd be looking at > something more along the lines of 32-64kb/s to get anything that you > could understand. It might be easier to make a phone call. > Conveniently enough, I think the device will have that capacity as > well. MP3 isn't for voice audio, it's for music audio (Which has a larger dynamic range and needs more resolution than voice-only audio). For voice-only audio, you'd be better served by a codec like Speex; one that is designed specifically for human speeking vocal range. I've heard completely understandable Speex recordings at about 8kb/sec. They didn't sound that great, but I could understand them. Going back to the original post, I'm not sure even Speex could help, as the biggest thing is going to be the latency of the audio. Cell phones have a bad enough lag just using the regular methods, but if the latency gets up over a second, then you'll be stepping on each other's side of the conversation. -KW ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
* Terrence Barr - Evangelist, Java Mobile & Embedded <[EMAIL PROTECTED]> [070202 17:56]: > VoIP calls typically require approx. 120 kbit/s *each* > direction, that's 240 kbit/s for a two-way conversation. > > UMTS gives you 384 kbit/s if you're lucky. Most of the time > it's more like 150 kbit/s, so VoIP will only work with > very poor quality. UMTS gives you only 64kbit/s upstream. Andreas ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
Salve ROB!
ROB schrieb am Freitag, den 02. Februar 2007 um 11:37h:
> Bit rate=sampling rate x bit depth
>
> 1kb/s isn't going to get you too much audio.
I wrote 1KB/s and I meant 1kB/s, or 8000 baud.
Already tested quality=0 speex and iax succsessful.
Maybe I did something wrong but this gives realy
a good enough quality - consider how old the GSM codec
is.
From my /etc/asterisk/codecs.conf
[speex]
; CBR encoding quality [0..10]
; used only when vbr = false
quality => 0
http://www.voip-info.org/wiki/view/Asterisk+config+codecs.conf
quality 0 = mode 1 = 2,150kbps.
From asterisk CLI:
-- Executing Dial("SIP/rob-c7c7",
"IAX2/astblufunk:[EMAIL PROTECTED]/17241") in new stack
-- Called astblufunk:[EMAIL PROTECTED]/17241
-- Call accepted by 84.16.228.211 (format speex)
-- Format for call is speex
-- Accepting AUTHENTICATED call from 84.16.228.211:
> requested format = speex,
> requested prefs = (),
> actual format = speex,
> host prefs = (speex),
> priority = mine
-- Executing Answer("IAX2/asttangop-10", "") in new stack
-- IAX2/asttangop-9 answered SIP/rob-c7c7
I promise to put examples on my webpage in 14 days.
Greetings,
rob
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Re: Voice over GPRS?
VoIP calls typically require approx. 120 kbit/s *each* direction, that's 240 kbit/s for a two-way conversation. UMTS gives you 384 kbit/s if you're lucky. Most of the time it's more like 150 kbit/s, so VoIP will only work with very poor quality. Also, most data plans specifically prohibit VoIP usage and may even prevent it technically. VoIP over cellular is just not feasible at this point. The pre-paid data is interesting, though, from a competitive standpoint. -- Terrence ROB wrote: Bit rate=sampling rate x bit depth 1kb/s isn't going to get you too much audio. Try encoding an mp3 at 1kb/s to see how audible that would be. I think you'd be looking at something more along the lines of 32-64kb/s to get anything that you could understand. It might be easier to make a phone call. Conveniently enough, I think the device will have that capacity as well. On 2/2/07, Robert Michel <[EMAIL PROTECTED]> wrote: Salve! Does anybody has experiances/ideas about Voice over GPRS? How long is the delay? It could maybe used for asyncron voice communication Talk2Talk (instead of pushing a button) In Germany did three Prepaid Provider published new Tariffs with 0.24Euro/MB. German pages: http://teltarif.de/arch/2007/kw05/s24754.html data cost calculator: http://teltarif.de/mobilfunk/datenrechner.html I think with this tariffs using mobil data becomes interesting ;) By using 1KB/s for audio and some overhead, let us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, 60 seconds makes then about 3 cents. When both using this 6 cents. Hmm that would be interesting when the user makes often make brakes/pause in their talk. Greetins, rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community begin:vcard fn:Terrence Barr n:Barr;Terrence org:Sun Microsystems adr:;;Zettachring 10 A;Stuttgart;;70587;Germany email;internet:[EMAIL PROTECTED] title:Evangelist, Java Mobile & Embedded Community tel;work:+49 711 720 98185 url:http://www.mobileandembedded.com version:2.1 end:vcard ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
* Robert Michel <[EMAIL PROTECTED]> [070202 17:06]: > Salve! > > Does anybody has experiances/ideas about Voice over GPRS? > How long is the delay? It could maybe used for asyncron > voice communication Talk2Talk (instead of pushing a button) The lag with E+ for GPRS/UMTS is at best in my experience 300ms, and sometimes goes up into seconds. Please consider also the fact, that GPRS is a low priority service. Hence for GPRS you get the following fascinating list of properties: a) high latency b) non uniform distribution of latency and bandwidth. c) at best analog modem speeds, albeit only download wise, upload wise you are often limited to 1 channel with 9600bps. d) no QoS support So the only "sensible" voice application over GPRS might be push-to-talk, which by the way is offered by some carries over GPRS :) > By using 1KB/s for audio and some overhead, let In many cases you won't be able to upload 1KB/s. > us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, > 60 seconds makes then about 3 cents. When both using > this 6 cents. Hmm that would be interesting when > the user makes often make brakes/pause in their talk. No way you can think of doing sensible full-duplex two way discussions. As an example, take WLAN. VoIP over WLAN works, because the involved bandwidths have a completly different ratio: Most sip providers claim 2x100kilobits/s as requirement, and even 11mbps WLAN has an useable bandwidth of 4-5mbps. Andreas ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
2007/2/2, Robert Michel <[EMAIL PROTECTED]>: Salve! Does anybody has experiances/ideas about Voice over GPRS? How long is the delay? I heard it could be pretty lond delay (like a second or more). It is hard to use programs such as skype. Walkie-talkie like solution is very interesting, though. ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Re: Voice over GPRS?
Bit rate=sampling rate x bit depth 1kb/s isn't going to get you too much audio. Try encoding an mp3 at 1kb/s to see how audible that would be. I think you'd be looking at something more along the lines of 32-64kb/s to get anything that you could understand. It might be easier to make a phone call. Conveniently enough, I think the device will have that capacity as well. On 2/2/07, Robert Michel <[EMAIL PROTECTED]> wrote: Salve! Does anybody has experiances/ideas about Voice over GPRS? How long is the delay? It could maybe used for asyncron voice communication Talk2Talk (instead of pushing a button) In Germany did three Prepaid Provider published new Tariffs with 0.24Euro/MB. German pages: http://teltarif.de/arch/2007/kw05/s24754.html data cost calculator: http://teltarif.de/mobilfunk/datenrechner.html I think with this tariffs using mobil data becomes interesting ;) By using 1KB/s for audio and some overhead, let us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, 60 seconds makes then about 3 cents. When both using this 6 cents. Hmm that would be interesting when the user makes often make brakes/pause in their talk. Greetins, rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
Voice over GPRS?
Salve! Does anybody has experiances/ideas about Voice over GPRS? How long is the delay? It could maybe used for asyncron voice communication Talk2Talk (instead of pushing a button) In Germany did three Prepaid Provider published new Tariffs with 0.24Euro/MB. German pages: http://teltarif.de/arch/2007/kw05/s24754.html data cost calculator: http://teltarif.de/mobilfunk/datenrechner.html I think with this tariffs using mobil data becomes interesting ;) By using 1KB/s for audio and some overhead, let us say 2 KB/s 0.24Euro/MB = 24 Cent for 500 seconds, 60 seconds makes then about 3 cents. When both using this 6 cents. Hmm that would be interesting when the user makes often make brakes/pause in their talk. Greetins, rob ___ OpenMoko community mailing list community@lists.openmoko.org https://lists.openmoko.org/mailman/listinfo/community
