[Nexus 5 General] dj_aj:
Disclaimer:

This may not be the right section for this thread but I didn't know where else to put it. And since I verified this setup on a Nexus 5, I figured this is the best bet.

I stayed in the US for a few years and have an active Google Voice number that my friends in the US call to contact me. Thus, I needed a free method to forward those calls to Canada.

Yes, There are a few of 3rd party apps like GrooveIP that not only let you receive calls but also make calls over data. However, I don't like 3rd party app notifications in my status bar constantly and needed a free solution that would work.

My solution however, only uses the default phone dialer app to receive forwarded calls over SIP.

Step 1

Get yourself a Google Voice number. There are many guides on the internet on how to achieve this via the use of proxies/vpn services.

Step 2

Create a free Sip2Sip account here: https://mdns.sipthor.net/register_sip_account.phtml

Once you receive the confirmation email, Login and go to the ‘Settings’ panel.

Uncheck Reject Anonymous, change the no answer timeout to 60 seconds and uncheck Voicemail Enable. Then click Save at the bottom.

Then click on the ‘Identity’ panel and leave that page open.

Step 3

Open a new browser tab and signup for an IPKall account here: http://phone.ipkall.com/

All the information to be filled out will be available on the ‘Identity’ panel on sip2sip.

Where it says SIP URI Username, enter your username from the account you created on Sip2Sip.

Enter sip2sip.info in the Domain field.

Choose any password and complete the signup.

Wait for IPKall to email you your new number and account info.

Step 4

Go to Google Voice Settings and click to Add a new number.

Choose a name for this number, I named it ‘Ipkall’ to make it easier to recognize. And type in the phone number that Ipkall emailed you. then click save.

More than likely, the IPKall number assigned to you may have already been used earlier by another Google Voice user. It’ll ask you to reclaim that number by verifying it. That’s okay, we’ll get to that in a bit.

Step 5

On your android device, open the Phone dialer and go to settings. Then open ‘Call Settings’.

Scroll all the way down to Internet Call Settings and click on Accounts. Make sure that there is a check mark next to Receive incoming calls. Then click on Add account on the bottom.

Enter your sip2sip username and password in the respective fields. In the server field, enter sip2sip.info. Then uncheck set as primary account and click on Optional Settings. Under outbound proxy address, enter proxy.sipthor.net

Then click save and wait for it to register. Once done it should say Receiving Call under “username@sip2sip.info”.

That’s it, go back to Google Voice settings and reclaim the IPkall number assigned to you. If you didn’t have this issue then you are already set to go.

Place a few test calls to your Google Voice Number and check to see if they’re being forwarded to your Phone over SIP.

BONUS:

You can also use this setup to get Google Voice to connect you to US phone numbers for free. Visit the Google Voice website, enter the phone number you'd like to call and choose your ipkall number as the phone to connect with. OR you could get a Google Voice call back app to do this on your phone.