OK, for you newbies out there (me about a year ago) - if your eyes start rolling when you read this kind of stuff it's alright, happens to the best of this. Try to follow it and do a search for other related posts and it will all sink in eventually.
As most are aware, GV stops supporting directly logging into and making calls from your GV account from Obi's and via other means (i.e. Groove IP) after May 14, 2014. While this change means you can no longer make or receive "pure" Google Voice calls directly with your OBI, Google Voice will still allow you to forward calls to another phone number regardless of where that phone number (or DID as it's known in the SIP world) is located.
With that in mind, from Callcentric you can get an IP Freedom account and two free phone numbers and use these to simulate how you currently use your Obi today. If you have one, two or even four GV #'s now, you can set your Obi up for incoming GV calls and make similated outgoing GV calls such that your callers would not know the difference. And your cost will be very minimal (as low as $1.50 / month if you only get incoming GV calls).
Again, an IP Freedom account is free. Initially with it you can only call other CC accounts and via SIP with no POTS (plain old telephone system) endpoints. What's cool though is that with an IP Freedom account, you can get two free unlimited incoming minutes DID's that are based in New York. CC makes money on these DID's by charging a termination fee to the carrier that originated the call. You can also make outgoing calls with these DID's with either a pay as you go plan where you are charged a couple pennies a minute or a monthly plan where you get unlimited outgoing for a few bucks a month. Callcentric mandates an E911 fee ($1.50 / month) if you will be using their service within the US or Canada.
Google voice allows you to forward two GV #'s to the same phone number if one GV # forwards to "home" and the other GV# forwards to "work". GV will only allow one # to forward to a given DID if the forwarding number is considered mobile when you set it up in GV. What this means related to CC is that you can forward up to 4 GV #'s to the 2 free CC DID's you can get with an IP Freedom account. The only issue with forwarding two separate GV #'s to the same DID, you cannot distinguish which one the call originally went to because CC forwards the CID that was sent from GV.
Expanding this further, Callcentric lets you spoof outgoing verified caller ID's by extension so you have the potential to have 20 spoofed numbers if you assign a different CID to each extension. Those 20 extensions are each sub accounts which means you can have 20 different softphones , ATA's PBX's, etc. logged into your account at the same time. Callcentric also allows you to direct an incoming call on one of your DID's to a ring group of extensions or to a specific extension.
On the OBI side, you have up to 8 outgoing voice gateways and a minimum of 2 sp's to play around with which means potentially 10 different outgoing caller ID's (using different CC extensions outgoing from the 8 VG's and 2 SP's with spoofed CID) depending on how your dial plan is set up.
Between the Obi and Callcentric, there are alot of options to allow you to simulate how you use your Obi now with Google Voice. What this means is that after May 14th, you can still use your Obi to make and receive GV calls with a little bit of additional setup by utilizing another providers services (in this case CC) to provide the connection to and from GV and the POTS network. It isn't entirely free but at a minimum of less than $2 / month with a commitment that can be cancelled at any time, you can make your Obi work exactly as it does now.
