I’ve been experimenting with my FreeRunner recently and came across some articles about free VoIP. As it turns out, thanks to Google Voice and a few extra services, it’s possible to both receive incoming and make outgoing calls completely for free. After setting these services up, I wrote a CLI utility that combines a Python Google Voice framework with Linphone in order to make the task of placing a call easy.
Getting free VoIP
You need three things: a Google Voice account, an Antisip account, and an IPKALL phone number. Go to each of these websites to create them. For Antisip, you can use your Google Voice number for the PSTN Phone. For IPKALL, you’ll need to provide the following information:
SIP Phone Number: [antisip username]
SIP Proxy: sip.antisip.com
After some time, you’ll receive a Washington state phone number.
Now, open up Linphone using either the GUI or the CLI client (probably easier with the GUI). In the preferences of the GUI, there is a tab called “Manage SIP Accounts;” go there. Add a proxy account with the following information:
Your SIP identity: sip:[antisip username]@sip.antisip.com
SIP Proxy address: sip:sip.antisip.com
Register at startup: yes
Now, Linphone should register. You can try calling a SIP echoline at sip:*firstname.lastname@example.org to see if things are working.
Putting it all together
Lastly, we want to be able to make free calls to regular phones, too. This is where the IPKALL number and Google Voice come in. Antisip only allows incoming calls. When you call a number from Google Voice, it first calls you and then calls the other person, thereby acting as a link between the two connections.
So, add the phone number you got from IPKALL to Google Voice and try calling a phone number from the Google Voice interface. It should call your SIP client first and then call the other number.
To make this process quick and painless, I wrote a quick Python script called gvcall. Basically, it makes the process of calling a number from your computer as painless as gvcall 5555555555. You can also use your non-VoIP numbers as well.