Looks like this was posted 4 months ago but I'll tell you want works for me after exchanging my Nexus 7 twice due to Bluetooth hardware issues. I use an app called Talkatone which hooks into a Google voice account numbers. At first I had Bluetooth issues with my Plantronics PLT510 and after many phone calls to Google Tech support, I had to exchange my Nexus 7 twice before I got one without problems. I don't know for sure it was a hardware issue but, I have no other explanation.

Now I can make Talkatone phone calls over with WIFI either at home or when I tether off my iPhone 5.

I started a thread somewhere with a bunch of Google Now commands.  I will look for the link.
Sent from my Nexus 7 using Tapatalk 2

Yup that seems to work from the Google Search only. The Maps for mobile Navigation (beta) program still thinks "2" is "to" yet 4 seems to work.

The last time I called Google they suggested that I contact Asus for more information and the last two times I called nobody ever heard of any bluetooth problems with the OS above jellybeen 4.2.1. One person went on to say that 4.2.1 has addressed the known bluetooth issues and he seemed to think that the issue was defective hardware. In my experience when you have features that only work on some devices and not others, it's typically either a firmware or hardware problem. I've been working with computer hardware since the early 90s, have a A+ certification and renewed it a few years back, and I'm considered the hardware go to guy for my company. This smells so much like a hardware problem it's stinking up the place. Since you can't update the firmware, replacing the device is the prudent thing to do.

I knew it, I found out today that it's a Hardware problem. Someone gave me one of these (the exact same one) for Christmas and it doesn't have the problem. I can use it as an IP phone with my bluetooth headset and it works perfectly. It has the same exact software on it as the one I puchased on 12/2. I called Google again today and they said they don't know what's going on and I would have to call the manufacture to get more information about the problem. Yea will bull Schit on that. So far I've made 12 phone calls on this one without a single problem. I went down to the retailer and retured the defective unit (second one) without any questions asked and it was 24 days old. Those of you sitting around waiting for a software update you bet be aware of what I went through.

Since the Bluetooth functionality is broken I'm in search of a wireless headset and Microphone, sort of like the Plantronics CS50-USB that will work with the Nexus 7.  I would be using it to redirect most of the sounds from the until to the wireless headset and mostly for making phone calls wirelessly.

From reading these messages my persecution was that the "N7 has an issue with bluetooth".  So what does that mean? Is it a HW or a SW problem? I couldn't tell. I called Google again tonight and they claim that jelly bean 4.2 is the issue and they rolled out 4.2.1 to address some of the Bluetooth problems but, he wasn't sure if that was supposed to resolved my issue. Again nobody seems to know if the problem is with the OS or the hardware manufacture. As a consumer of these products I have a right to know! I have a right to a product without flaws and when there’s problem a public disclaimer that states the correct facts. That’s why IBM, HP, Microsoft, Apple and a whole lot of other companies publish customer advisories. They know they have to keep people informed otherwise the consumer market will eat them alive. So, again I don’t think I’m the one here that doesn’t get it..

I guess they do. As it stands right now I’m feeling like I have an inferior product  . I called Google Support using my iPhone 4 with the same VOIP app and the Plantroics PLT 510. The sound was perfect  . The person I spoke to said that I was pushing the limits of the model (Nexus 7 16gig) and that’s why it didn’t work. He actually wasn’t really sure why it wasn’t working and when on to say I should go to the Nexus 7 – 32. So, I went back to the retailer and exchanged the unit for a Nexus 7 32gig and guess what? It has the same exact problem  . At this point I'm not sure if it's a problem with the Hardware or Jelly Bean. If I knew that, I could make a decision on whether or not I'm going to keep the unit.  Otherwise I’ll have to take it back because having the ability to make VOIP calls is important to me. If this little iPhone can do this, why not this Asus unit?

I've just updated this as I had two different model headsets to test with. I'm starting to think I have a defective Nexus unit.
I’ve tried a couple of these Plantronics Bluetooth plt 510 and Model 330 bluetooth head sets ear piece that I have been using with my iPhone and Windows XP machines around the house. I typically only use them for phone calls either will the default phone or a google voice phone app. On the Nexus 7 I can get them to pare but when I make a phone call and redirect the sound the earpiece and it begins to screech like an AM radio next to a neon sign with a short in it. Ok so I’m showing my age now. For those of you that don’t know what AM radio is, please see Paul Harvey. 

I have not had the opportunity to test any other Bluetooth ear pieces besides the PLT 510 and Model 330 yet. I’m wondering if anybody has with the Nexus 7 and a compatible google voice phone app.