Google Voice + Sipdroid = Transparent Free International Calls

  Android is really exceeding all of my expectations. One fantastic feature of the Android platform is that all of the apps are on an equal footing. Third parties can hook into Intents and even replace whole features. Even the dialer.

Enter Sipdroid which is an open source SIP IP phone protocol client for Android. Sipdroid can either replace the dialer entirely, replace it when you have data network support or just hook the dialer so that when you dial a number ending in + with the built-in phone app, the call is made via Sipdroid.

Sipdroid works best with a freemium virtual call routing service, appears to be based on Asterisk and is sponsoring the development of Sipdroid. Google’s Gizmo5 “Guava” app is based on Sipdroid.

Things are tricky to set up mostly because of a derth of documentation and misleading error messages, but here is the gist:

  • Sipdroid talks to (theoretically not required)
  • has one or more “trunks” which are logical phone lines. The trunk is a way to connect your 3rd party SIP phone account. (Pbxes will suggest some if you don’t already have one.)
  • has one or more extensions and inbound and outbound routes. At its simplest, there is one trunk, one extension, one inbound route.
  • If you want to be able to send calls, then Pbxes needs an outbound route.

Sipdroid has several codecs so it can automatically scale the call quality to the available bandwidth. in the screenshot below, I have a call over Edge at 11Kb/s using thespeex codec.


















This is fantastic because what it allows me to do is have a SIP phone number in the USA that forwards calls to my phone when I am overseas as long as I have data service from the GSM network or from WiFi.

Voice Makes it Transparent

I want something even better. I want a single voicemail box and I don’t want people to have to know to call my SIP number. I want it all to be transparent. The key to this is doing an unconditional forward of my old number to Google Voice.

While offers basic voicemail service and will even email you an audio file, what I really want is to use my Google Voice voicemail.

You need a Google number and then use Google Voice to ring the SIP number and my Skype-out number, too. Google Voice says that it will only forward SIP calls to Gizmo5 accounts but it will actually forward to anything that has a dialable phone number.


google-voice-routing It’s important to set the call timeout as long as possible on your SIP service to make sure that Google Voicemail will kick in before a network error does. Also, be careful not to create a dialing loop. If you are forwarding calls from a number to Voice, don’t have Voice dial that number. (See above where Voice is not dialing my AT&T number because that is what is forwarding to my Google number.)

Once I Google Voice is set up to forward to Sipdroid (and Skype), I can turn on forwarding of my old telephone number to Voice anytime I am going to be out of the country and I present a single number to the outside world and people can call me overseas without incurring any long distance charges. It is totally transparent to them. They don’t have to know about any of these numbers used to route the call.


11 Responses to Google Voice + Sipdroid = Transparent Free International Calls

  1. kit says:

    Nice idea in theory, but from what I’ve heard Google Voice is inaccessible overseas. I have a Google Voice -> ->SipSorcery -> Sipdroid thing set up all nice and pretty, but I am concerned I will be unable to access my VM because (a) I have read that google voice service is blocked from any out-of-country IPs and (b) I cannot seem to reach my Google Voice Mailbox by dialing my google voice number from sipdroid.

    What confuses me most about this is that Google definitely knows the IPKall number, because when I dial any numbers in SipDroid, the caller ID resolves as my Google Voice number.

    So what’s the work-around?

    • Brian Reiter says:

      I don’t understand why your caller ID is resolving to your Google Voice number. That doesn’t seem right.

      I have Google Voice forwarding to my Callcentric number. I have talking to Callcentric and Sipdroid is talking to

      My VMs are delivered to the Google Voice app on my Nexus One as long as I have data service. There’s nothing inaccessible about Google Voice overseas except that they only give you domestic USA numbers to use.

      I never tried calling to get my VM before. I just did it using Sipdroid and it works fine. I have Sipdroid using the Phone dialer as the preferred call type. Here’s what I tried:

      – Dial my Google Voice number followed by + to activate Sipdriod’s dialer (e.g. 1 (123) 456-789+)
      – When VM picks up, pull the dial pad up from the (5) icon at the bottom of the screen.
      – Dial *
      – Dial PIN when prompted

      I also tried this:
      – tap-hold my number in the call log
      – Select Text
      – Select Sipdroid
      – When VM picks up it’s the same as above

    • Jim says:

      Please i need your assistance. I bought the htc desire z and already have Google voice on it.. i also opened an account with pbxes and sipdroid. i have no idea how to connect it all. Would like to be able to call International. Please respond.


    • swamy says:

      Hi Experts….I have a serious problem with Sipdroid, GV, GV Callback. Please help me:

      I am from AP and I have a Samsung CDMA Galaxy POP with 2.2 Ver Android on it using Tata Indicom. I have been going through lot of articles since one year and today finally i have successfully got activated GV using IPtel sip address and express Talk softphone installed on my desktop finally.

      But now I am able to get incoming call when i trying to place a call to my GV or IPkall number but not able to converse unlike on desktop. why ? It s getting blank that it.
      Further, I keep on in illusion that we can make free unlimited out/in calls around the globe using GV, Sipdroid, GVcallback, IPkall. If I am right then please guide me. When am trying to call a contact (indian) GV callbacks works but i get a message with very low voice that no credits.

      Further, as i have not used (failed earlier), but used sip address on sipdroid, when i m trying to press new pbx with GV connect button (as its directed somwhere, i dont know exactly this trunk, in and out jargon), it says already connected with swamyllvoice where as i just want to cancel this and make it as swamyllb. What is the essence and how to configure trunks to make really free in/out calls around the globe ? please suggest.

      swamyhrd at gmail dot com GV 512-553-2769

      also gone through this link but confused:

    • Cary says:

      I personally have accessed my Google Voice from China. Also my GV shows up on My Caller ID.

  2. Robert says:

    Brian, I opened all the accounts listed and began connecting them, but cannot seem to get it right. Can you provide some help?

  3. Jason says:

    Great article, thanks for writing this up! I just recently set this up on my Android and everything is working properly (inbound/outbound calls) EXCEPT that missed/unanswered calls never make it to my Google Voice voicemail which is the key to this whole thing. Callers report that it just rings and rings and eventually disconnects. I’ve tried increasing my timeout on PBXes from 30 secs to 40, 45, and 60 secs. but still nothing. I’ve also tried disabling the PBXes voicemail to no avail. Is there an extra step to get my calls to my GV #, hit sipdroid if I’m signed in, but if I don’t answer, actually be picked up by my GV voicemail?



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  5. imanjunk1963 says:

    I installed sipdroid on my cell. I used the path via the button that wason the bottom during 1st time setup. Gave it my google talk id and password so it could create the same on pbx site. For a while I was able to call out successuflly using Wifi or 3G. Now I can’t do that after trying to debug why I could not ever make calls in to my sell. Now I can call out from mycell with the target phone ringing, I answer it and I can hear on my cell. But when I speak in the cell they don’t hear me. This is my cell to a house phone or to someone elses cell. They don’t hear me. Any ideas I have set wrong particularly on my GOOGLE VOICE account? I have GOOGLE VOICE CHAT selected on phones. I do not have my Cell or Home number selected there for forwarding but just listed. Some how I created a loop. When I speak in my cell, I hear myself as something else I noticed. Also besides the Phones tab on GV, is there any relation to the group settings?

    • imanjunk1963 says:

      By changing my server under the main account in settings on my cell from to fixed both of my problems. I can now make calls and receive calls. I think i messed up my pbxes profile when I tried to set my time zone from www4.???? that was there by default to a NY one. I bet by doing so I over wrote the default setup that sipdroid did/or did not do when it created my account. Now my sip account shows instead of the same but

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