If you think you should use Google Voice on your Nexus 7 tablet to make and attend phone calls then you should follow the below guide:
REMEMBER: Upon rooting your Nexus 7 tablet, the warranty will be expired or you may also end up with a bricked device. So follow this guide at your own risk.
Note: In this guide we have our nexus 7 tablet rooted and we already have a Google Voice account.
Step#1: Configure a VoIP account from any service. After that configure an account from any service that allows VoIP calls incoming without any charge.
Step#2: Now download and install CSipSimple [Google Play store] and configure it with your VoIP account.
Remember: The username you choose will also be your contact number.
Step#3: At this point, insert a new number (the number which you got from the selected VoIP center that lets you receive free incoming calls in Step#1) into your Google Voice account from the settings panel.
Now you will be able to receive calls on your Nexus 7 tablet. The further steps will activate the call making procedure:
Step#4: Now download and install Voice+ from this link [Google Play store] and configure it with your Google Voice account.
Step#5: Now download ExDialer from the Google Play store which shall be use to enter the number you want to call to.
Step#6: Now download the FrameworkFlasher-MOD.zip from this link. Decompress the file contents using 7-zip or similar software.
Step#7: Now use a root-enabled file explorer such as File Expert for navigating to /system/framework and locate the framework-res.apk. Now copy this file and paste it under the folder named “place-framework-res-here” that you decompressed in Step#6.
Step#8: At this point launch the “RunMe” application that you had decompressed in Step#6. Recompile the framework-res using this app.
Step#9: Now the APK file will appear under the “files-to-edit” folder. Head over to the framework-res.apk > res > values and run the “bools.xml” file.
Step#10: Now find the phrase: “line false”. Once you find it modify the value of “false” to “true”. After doing this save the file!
Step#11: Again run the “RunMe” app and select the “option#2” for compiling a new APK.
Step#12: At this point select “Option#3” in order to sign the APK.
Step#13: Now select the “option#4” to generate an “update.zip” file.
Step#14: Now move this “update.zip” file to the /sdcard directory on your tablet
Step#15: Now switch off and start into “ClockworkMod Recovery” (which should have already been done if you rooted your Nexus 7 and already taken a NANDROID backup).
Step#16: Now head over to install zip from sdcard -> choose zip from sdcard -> update.zip and reboot your tablet.
If above steps were executed properly, your Nexus 7 tablet will be able to make and receive calls via Google Voice.