Topic: VOIP Telephony via Google's Grandcentral

Chumby seems to be perfect to provide interface for internet/pstn calling with Grandcentral. Grandcentral is running in beta since Google acquired it last year. It allows to initiate call between any 2 US phones for free from web browser, so it should be pretty straightforward with Chumby. GC also support Gizmo SIP accounts, so you could access your unlimited phone directory and call Gizmo/SIPphone VOIP unlike using cordless phone with 15 number memory. I have just discovered GC myself but it seems great.

http://www.grandcentral.com/

Re: VOIP Telephony via Google's Grandcentral

GrandCentral does not have developers' API, so (unfortunately) there is no way to get to the information they have. The only way I can see is for Chumby app to implement SIP client protocol and try using that to talk to Gizmo. But I think that would be a bit heavy, plus there is no crossdomain.xml on Gizmo Project's website.

But the idea is in the right/interesting direction.

Re: VOIP Telephony via Google's Grandcentral

Without the API, it might be able to be done with cURL ? Since it is "In Theory" just acting as the browser

Re: VOIP Telephony via Google's Grandcentral

The Wiki (http://wiki.chumby.com/mediawiki/index.php/General_FAQ) says "the VOIP client would probably be beyond current hw capability". For comparison, Nokia N800 tablet has Skype, Gizmo and other their own voip client working just fine, even with video streaming!

Chumby has 350MHz Freescale iMX21 MC94MX21DVKN3 ARM9
vs.
N800 has 330MHz TI OMAP 2420 CPU

When I look at the CPU usage, it's 10-30%. Is it a memory problem then? OpenWRT can run Asterisk on ~200MHz CPU wireless routers with even less resources (http://www.voip-info.org/wiki-Asterisk+Linksys+WRT54G).

5 (edited by KMyers 2008-03-05 01:16:07)

Re: VOIP Telephony via Google's Grandcentral

It is true that the hardware does not need to be super powerful to work with VoIP and it is possable on the chumby (If someone has the guts to try it). I think the biggest problem is the Microphone input, Using the built in Mic would give feedback with the speakers (Inless you used a headset)

Google Grand Central is not exactly a VoIP Client. It is a "Switchboard ACD" application. It basically calls two phones and connects them, which can be done on any hardware (via cURL)

Re: VOIP Telephony via Google's Grandcentral

To be clear, nobody at Chumby wrote that particular FAQ entry - we have indeed run some simple SIP-based VOIP clients on the chumby device and they work OK.

Re: VOIP Telephony via Google's Grandcentral

Should feedback no more than a telephone set to speakerphone. Also the microphone and speakers are faced in opposite directions, should be helpful.

Re: VOIP Telephony via Google's Grandcentral

I know GrandCentral isn't classic VOIP client but it seemed to be a great fit with Chumby concept: simple touch interface to initiate call, if you need to move away from Chumby, you can transfer the call to any phone/cell.

Duane, the FAQ entry on Chumby's VOIP limitation is here :
http://wiki.chumby.com/mediawiki/index.php/General_FAQ
I don't see who wrote it but assumed it's been blessed by chumbians.

Re: VOIP Telephony via Google's Grandcentral

miros wrote:

Duane, the FAQ entry on Chumby's VOIP limitation is here :
http://wiki.chumby.com/mediawiki/index.php/General_FAQ
I don't see who wrote it but assumed it's been blessed by chumbians.

We don't moderate the wiki except for spam.

The wiki is set up for the use of the community - while we may edit things every now and then when we run across things that are in error, we don't actively monitor it for accuracy or completeness.

Re: VOIP Telephony via Google's Grandcentral

So if you have already tested a VoIP solution and it worked great, are you at the moment thinking about a widget that could be added onto the chumby ?

A simple VoIP softphone wher you can edit your SIP account + STUN server for NAT problems would be easy to make I guess. I'm not a developper but from a theory point of view, I think it's only a matter of small developping time ?

Owner of 1 chumby in France
Facebook Group for Chumby

Re: VOIP Telephony via Google's Grandcentral

>>- we have indeed run some simple SIP-based VOIP clients on the chumby device and they work OK

Duane:

    Can you please give us pointers or info on those sip-based voip clients you have tested on the chumby?  I am seriously looking into writing a sip phone for the chumby

KingDavid

Re: VOIP Telephony via Google's Grandcentral

The one we had the most success with was pjsua.  We were specifically looking for something lightweight that *didn't* have a UI, so that it could be driven from Flash.  It's a pretty straightforward build - but you'l need to turn off cancellation and choose efficient codecs.

Re: VOIP Telephony via Google's Grandcentral

I was looking at pjsua too... it doesn't have g729 support though...although codec support on a sip client is a bit of a job, it is doable... I am officially working on a sip client for the chumby now... anyone who wants to pitch in, welcome.

KingDavid

Re: VOIP Telephony via Google's Grandcentral

KingDavid wrote:

I was looking at pjsua too... it doesn't have g729 support though...although codec support on a sip client is a bit of a job, it is doable... I am officially working on a sip client for the chumby now... anyone who wants to pitch in, welcome.

KingDavid

I think you should look a bit more on the G.711 codec as it uses less processor compared to the G.729.

Owner of 1 chumby in France
Facebook Group for Chumby

Re: VOIP Telephony via Google's Grandcentral

>>>I think you should look a bit more on the G.711 codec as it uses less processor compared to the G.729.

  Of course it uses less processor, g711 means "no compression"... you will need 64K though... in voip you need to get that signal to the other side asap.  You may have 64k available, but the other side might not.  Wi-fi definitely is always a potential factor that lowers quality.  Compressed calls use from 10k to 30 tops... g729 is proprietary, however.

King Dave

Re: VOIP Telephony via Google's Grandcentral

Duane,

which codec have you used? The audio playback is awful and to fast (sounds like Mickey Mouse).

Re: VOIP Telephony via Google's Grandcentral

this may be better asked to the pjsip developers, but thought I'd try here first:

did any of you have to specify what audio device with pjsua? (and if so, which one?) -- didn't have any trouble building the pjsua binary, scp over, runs just fine (a little slow), can put in registration + STUN config, UA registers fine. (this is pjproject 1.5.5 btw)

if I do specify playback device (0,1,2 etc.) pjsua crashes. if I specify -1 or don't specify (which defaults to -1) then it runs ok until making calls and gets:

16:50:59.598  pjsua_media.c  Unable to open sound device: Unable to find default audio device (PJMEDIA_EAUD_NODEFDEV) [status=420006]

for outgoing calls, or for incoming call:

17:04:46.756  pjsua_media.c  Opening sound device PCM@16000/1/20ms
17:04:46.760  pjsua_media.c  Opening sound device PCM@44100/1/20ms
17:04:46.761  pjsua_media.c  Opening sound device PCM@48000/1/20ms
17:04:46.761  pjsua_media.c  Opening sound device PCM@32000/1/20ms
17:04:46.761  pjsua_media.c  Opening sound device PCM@16000/1/20ms
17:04:46.762  pjsua_media.c  Opening sound device PCM@8000/1/20ms
17:04:46.762  pjsua_media.c  Unable to open sound device: Unable to find default audio device (PJMEDIA_EAUD_NODEFDEV) [status=420006]
17:04:46.762  pjsua_media.c  Error opening sound device: Unable to find default audio device (PJMEDIA_EAUD_NODEFDEV) [status=420006]

I built it like this, using the wiki instructions and arm-2008q3 toolchain:
./configure --build=i386-linux --host=arm-linux --prefix=/mnt/usb/pjsip --disable-l16-codec  --disable-gsm-codec  --disable-g722-codec --disable-g7221-codec --disable-speex-codec --disable-ilbc-codec --disable-speex-aec

I only copied over the executable, are there some missing libraries it wants? the only ones I can see in the binary are stuff that should already be there:
/lib/ld-linux.so.3
libm.so.6
libnsl.so.1
librt.so.1
libpthread.so.0
libc.so.6

pjsua-arm-unknown-linux-gnu: ELF 32-bit LSB executable, ARM, version 1 (SYSV), for GNU/Linux 2.6.14, dynamically linked (uses shared libs), not stripped

if it's not pilot error, could it simply be whatever version you guys tried back in 2008 played nicer with the chumby?

thanks

you can't phone home if you don't have a home phone

Re: VOIP Telephony via Google's Grandcentral

Bump.  I am having the same problems too.  I think it has something to do with ALSA.  Can maybe a dev suggest how to configure pjsua so it sees the sound device?

Re: VOIP Telephony via Google's Grandcentral

anybody from Chumby have any suggestions on how to build this?  i'm getting the same audio device error and have spent hours on this