Let me get this out of the way first: the Nexus 7 is not a smartphone, nor is it a tablet designed for incoming / outgoing calls like the original Galaxy Tab from Samsung. The Nexus 7 is a very basic tablet that is meant for doing tasks like surfing the web, socializing on Facebook, Twitter, sending / receiving email, play games, video chat via Skype or Google Talk etc. i.e. nothing to do with phone calls.
But, if you want to, there is a way to make your Nexus 7 handle phone calls. It’s not particularly straightforward as you will be required to set up multiple accounts and apps and even, in one part of the guide, modify an APK file, but if you take backups prior to strictly following the guide, you should do just fine.
DISCLAIMER: You will void your warranty after rooting your device. Redmond Pie will not be held responsible for any damage incurred to your device as a result of following this guide. Follow at your own risk.
Note: This guide assumes that you have rooted your Nexus 7 and have a Google Voice account.
Step 1: Set up a VoIP account from a service like CallCentric.com. Then, set up an account from a service like ipkall.com that you lets you receive VoIP calls for free.
Step 2: Now, download and install CSipSimple from Google Play and set it up with your CallCentric account (note that your username is your contact number on CallCentric).
Step 3: Add a new number – the number you received from ipkall – to your Google Voice account from settings.
You can now receive calls on your Nexus 7. Lets work on making calls.
Step 4: Download and install Voice+ from Google Play and set it up with your Google Voice account. Also download ExDialer from Google Play as you will be using to enter the number you wish to call to.
Step 5: Download developer bongostl’s FrameworkFlasher-MOD from the thread link at the end of this post. Extract its contents using a suitable software like 7-zip.
Step 6: Using a root-enabled file explorer like File Expert, navigate to /system/framework and you will find framework-res.apk. Copy this file and place it under the place-framework-res-here folder which you extracted in Step 5.
Step 7: Launch the RunMe application which you extracted in Step 5. Use it to recompile your framework-res.
Step 8: You will now see an APK file under files-to-edit folder. Navigate to framework-res.apk > res > values and open up the bools.xml file.
Step 9: Look for a line that says line false and change value of false to true. Save this file.
Step 10: Once again, launch RunMe and choose option 2 to compile a new APK.
Step 11: Now choose option 3 to sign the APK.
Step 12: Choose option 4 to create an update.zip file.
Step 13: Transfer this update.zip file to directly under /sdcard directory on your Nexus 7.
Step 14: Reboot into ClockworkMod Recovery (which you already should do if you have rooted your Nexus 7 and taken a NANDROID backup).
Step 15: Navigate to install zip from sdcard > choose zip from sdcard > update.zip.
Step 16: Choose reboot system now.
You should now be able to send and receive calls from your Nexus 7. For queries, please visit the official thread over at XDA-Developers.