Make free VoIP calls to U.S. numbers from Android (even from abroad!) using Gizmo5, Google Voice, Sipdroid and GVoice Callback

I’m home in Mexico right now, and I was looking for the cheapest way to call people in the U.S. I happened to have a Gizmo5 account from a long time ago, and I snatched a Google Voice account when it was GrandCentral, and I found out you can use the two together to call U.S. numbers for free with VoIP wherever you are. It turns out my internet here is fast enough for VoIP, and I don’t have a data plan but I don’t mind having to call over wi-fi, so it was a great solution for me.

There’s actually lots of places online that tell you how to get Google Voice and Gizmo5 working together, but I went a bit farther and got the whole method working on my Android phone. I guess, for me, mostly just to feel like I’m making a free true phone call to the U.S., but it’s also useful if you are in someone else’s wireless network with no access to a computer, or if you have good enough 3G (I think it works on 3G as well but don’t take my word for it). In any case, here it is (I am, of course, assuming you have both Gizmo5 and Google Voice accounts):

Register your Gizmo5 phone number on Google Voice

(I read somewhere that you can’t add a Gizmo number to Google Voice unless you have at least one regular, verified U.S. phone added first, so make sure you have that, in case this step is not working for you).

The reason you have to use both services together is that Google Voice does not make calls in itself. It only makes calls through the phones you register with it. So we are gonna register the Gizmo5 number so that GV can make calls through it.

Since the method GV uses to make calls with your registered phones is to call them and thus connect them with the actual number you want to call, this works for free with Gizmo5, because all it sees is an inbound call from GV, and these are free of charge.

First you need to register your Gizmo5 number with Google Voice so it can be used as a callback number. Log onto Google Voice, go to Settings > Phones and click on Add a new phone. Give the number a name (I did “Gizmo”), write your Gizmo5 phone number and select “Gizmo” from the Phone Type drop-down menu.

Add your Gizmo5 number to Google Voice

Add your Gizmo5 number to Google Voice

You can already make calls for free on your computer

This is actually all the setup needed to make free calls using your computer.

  1. First open your Gizmo5 phone. This can be done either on the web interface by signing onto your account on, or by downloading the Gizmo5 desktop app for your OS here and signing on to it (on an interesting sidenote, my Mac app used to be stuck “Connecting…” and it turned out it was cause I had a symbol in my password, which Gizmo5 itself does allow but apparently the app doensn’t? Kinda humorous but maybe applicable to you)
  2. Once you have Gizmo5 open, you need Google Voice to actually connect the call. Log into Google Voice, click on the Call button on the top left and write the desired U.S. number you want to call, then select your Gizmo phone from the Phone to ring drop-down.
  3. Start the call on Google Voice

    Start the call on Google Voice

  4. Finally, click on Connect. This should ring your Gizmo5 phone, which will simply detect a call from Google Voice. Answer that call on Gizmo5 and you will be connected to the number you dialed from GV.

If you’re happy with calling from your computer over the Gizmo5 interface, you’re done! To use this method on Android, keep reading below. Basically, Sipdroid and GVoice Callback will do on Android the job Google Voice and the Gizmo5 client (or web interface) do together on a PC, respectively.

Install and setup Sipdroid

Note: If you have the actual Google Voice app installed on the Android phone, you should have it NOT be the default for outgoing calls by going to the app and then Menu > Settings > Do not Google Voice to make any calls (or Ask every time I make a call).

Sipdroid will act as the Gizmo5 client on the Android phone. Go to the Market and search for “Sipdroid”. The actual app is called “Sipdroid VoIP”. Download and install it.

Open Sipdroid and go to Menu > Settings > SIP Account Settings. Fill these out as follows:

  • Authorization Username: Gizmo username or Gizmo number (747*) will work. I used username.
  • Password: Gizmo password
  • Server:
  • Domain: leave empty
  • Username/Caller ID: leave empty (Important! Apparently there’s a bug unless you leave this blank)
  • Port: leave default (5060)
  • Protocol: UDP

Sipdroid setup

Sipdroid setup

You should see the notification icon go green once your settings are correct. For Preferred Call Type, choose Phone so it (like the Google Voice app) doesn’t interfere with outbound calls.

Have Sipdroid not interfere with outbound calls

Have Sipdroid not interfere with outbound calls

Additionally, if you’re planning to try this over 3G, you should check Use 3G inside Call Options.

Setup GVoice Callback to be able to catch outbound calls and connect them through Gizmo5 (Sipdroid)

That’s it for Sipdroid. Leave it open (it stays open anyways even if you click Back or Home). Go back to the Market and search for “GVoice Callback”. Download and install.

Open the app and fill out the main screen as follows:

  • Callback is enabled when…: I have this set to Ask me every time. This allows to either make a normal call when I dial a number or choose to make it through Sipdroid using GV.
  • Your callback number: Your Gizmo5 number
  • Phone type: Gizmo (Important)
  • Google Voice login information: speaks for itself
GVoice Callback setup

GVoice Callback setup

Click on Finish. GVoice Callback should work for a bit logging you into GV, then it will say the settings are saved and exit automatically.

Make a call from your Android

Make sure Sipdroid is running (the green circle should be in the notification bar), and wi-fi (or 3G), obviously, then simply dial a U.S. number on Android the way you would for any other number (that is, use the Dialer or click on their phone number from the Contacts app or whatever). The way I set it up on GVoice Callback (Ask me everytime), I get a popup asking if I want to place the call using GVoice Callback or call normally. Click on Use GVoice Callback.

Use GVoice Callback

Use CVoice Callback

That’s it! GVoice Callback will work for a bit:

GVoice Callback connecting the call

GVoice Callback connecting the call

Then it will call Gizmo5 (Sipdroid) and connect the call. Same as the desktop Gizmo5 client, Sipdroid only sees an inbound call from GVoice Callback, so it’ll open and you have to slide up to answer the call. At this point you will, at last, be connected to the original number you dialed:

Slide up to answer the call

Slide up to answer the call

I hope this is useful. Again, since it’s an inbound call to Gizmo5, you don’t get any balance deducted (in fact I have no balance on Gizmo5 at all). The method works well for me. Sound quality is decent over my wireless network, and hey, it’s free after all! Feel free to leave comments about 3G performance if you give it a try.

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