[General Topics] br0adband:
For those needing more info about using Google Voice for calls...

GrooveIP and Talkatone are by far the most popular apps to use with Google Voice (on an Android device).

Google Voice itself is not VoIP capable nor is it by itself a VoIP service - so many people just don't seem to get this, they think because it's called "Google Voice" it must be some VoIP thing and that's exactly NOT what it is. When coupled with Google Chat (which will be merging into Hangouts soon enough) it can be capable of VoIP duties but that's where GrooveIP and Talkatone and some other apps come in, explained below.

You are required to have a Google Voice account + Google Voice number - you get one when you register for the service by going to voice.google.com and setting things up - you WILL need a phone number to get the registration handled, however because they have to have a contact number to reach you by (SMS/Voice/etc). It can be pretty confusing for some folks so here's how it's done:

1) Go to http://voice.google.com and sign up for an account if you don't already have one. You may find yourself with a Google Voice number that isn't even in your area code when the choices become available - as Google Voice continues to grow in popularity the amount of numbers available decreases since they're assigned just like regular old phone numbers. Try your area code, if nothing exists, try a different area code - I personally have 4 GV numbers and only one of 'em is in the Las Vegas are, the rest are in completely different places in the US (figured I'd spread 'em out). You will be required to provide an actual landline or cellular number to receive a message (voice or text) with a confirmation number you have to punch in to finish the registration.

2) At this point your cellular service needs to be active meaning the device you intend to use for Google Voice + GrooveIP/Talkatone "phone" calls because you'll have to link the Google Voice account to that number after you install the app - this is a different confirmation process than the one you just completely by signing up for Google Voice itself.

3) When that's all set up, download the Google Voice app on your Android device from the Play Market and install it, go through the steps to set it up and use the cellular number the device has when requested. You can also handle setting up your Google Voice voicemail during this process too.

4) When that's all done, now you can install GrooveIP or Talkatone. I tried GrooveIP myself in the past, didn't like it, so I use Talkatone personally. I can't go into the finer points of the installation and set up at this moment because I don't even have a smartphone presently, so you can step yourselves through the process, it's not tough at all, just provide the sign in info for your Google Voice account - GrooveIP/Talkatone work like middle-men between you and Google Voice so this info is required, you can tell it not to save the password/etc if you're paranoid and also to not run those apps when you reboot the device meaning you manually start it. All that stuff is configurable in the options.

5) When all this is set up, here's perhaps the biggest tip I can offer: you need to go back to the Google Voice account online (http://voice.google.com) and go into the settings and disable the notification service that forwards calls/texts to your mobile number - meaning you need to select ONLY Google Chat. If you do NOT do this, what happens when you get a call or a text is that your phone will ring twice: it'll get a call from the VoIP software (GrooveIP or Talkatone) alerting you that you have a call, and it will ring your actual cellular number because it's forwarding things from the Google Voice number to your cellular number. It gets confusing as hell when your phone rings and you answer it not realizing that you're chomping off your airtime minutes thinking you're answering a call with the VoIP capability. By selecting only Google Chat (which is what GrooveIP/Talkatone are connecting to and using) that means the phone will just notify or ring only for pickup using those services - your T-Mobile minutes won't be touched at all.

Just make sure you go into the Google Voice account settings (you can't do it from the mobile app, has to be done from the website) and disable/uncheck the box to forward calls and texts to the Google Chat account (which is what GrooveIP/Talkatone end up using for their purposes).

Hope this helps and makes sense, I'll answer questions if necessary but it's fairly simplistic. Been using GV + Talkatone for almost 18 months now without issues, I can even make calls using 2G/EDGE (when I have a smartphone, that is) without any noticeable problems. Talkatone recently switched over to using Opus as their voice codec and the bandwidth requirements for a voice call are about half what they used to be with audio quality remaining almost the same as the previous codec (higher bitrate Ogg Vorbix Speex).

Anyway, that should get you folks going on this. I rarely if ever use any of my 100 minutes on the T-Mobile $30/month plan because of this setup. Of course, when May 2014 rolls in and Google pulls the plug on GrooveIP (who have already announced they're closing up shop at the end of April 2014) and Talkatone (no idea what their plans are as of yet) we'll all have to find some other way to use VoIP or pay for the minutes as required I suppose.