VOIP Tech Chat → help setting up voip with google voice

hello, im new here. i am looking for some help setting up a cisco cp-7940g voip phone with my google voice number for incomming and outgoing calls. i already have the google voice number and a free SIP account already set up, but i am kinda lost as to what todo next. i do have basic networking experience and ran the cabling already. the phone does connect to the switch and gets an ip address. im looking todo this whole thing for free. your help is greatly appreciated!

Well, you can get incoming calls easily enough. Get a free IPKall DID number (assuming any are available) and forward it to your SIP URI. Then forward your Google Voice number to the IPKall number. Correct caller ID isn't working with this right now.

Or you could do the same thing with a free Callcentric IP Freedom account and a free Callcentric DID.

But for outgoing calls, you will not be able do this with Google Voice directly with your Cisco phone. You can use a web browser to initiate a callback from Google Voice easily enough. But pick up the phone and dial out via Google Voice? Nope.

Google Voice is not designed to be used with an IP phone.

In other words, Google Voice does NOT provide direct SIP connectivity.

There are some 3rd party workarounds, most notably having an ATA from the Obihai company, but Google is ending their support for XMPP in a few weeks which probably spells the end for such backdoors.

There are places and ways to get free inbound service, but no one is going to offer free outbound service these days.

There are a wide variety of SIP-friendly VoIP providers often discussed in this forum.

By the way, your Cisco phone probably does not natively work with SIP, special modifications are required. Cisco has a different system called SCCP.

The easiest way to use GV to make and receive calls is using Obi devices for now. It will likely not to work after May 15, 2014. I have wrote a couple of how-to about this, as referenced below. However, you will need a Linux box to do the processing besides the ATA/VOIP phone/Softphone.
For now you can take a look of this one (»forums.plugpbx.org/index ··· ic=247.0) and for after May 15, there's another one: (»hobbiesbytwinclouds.word ··· ut-xmpp/).
I would suggest go to the second one directly.

I wouldn't categorize the use of a published API as a "backdoor". This is just the "Curse of the Third Party Solution" in effect. You never know when the Party of the First will nuke the API for one of their products and put a crimp in your business plans. (In this case, Plus is nuking Chat with Hangouts... fallout to come... )

Wasn't meant to be pejorative.

Sometimes connecting by the backdoor is fun.

Oh, I didn't interpret it that way. (How rude!)

I don't think Google was ever bothered by Obihai's solution. Actually, I think Google liked the additional enabling of Voice. They just didn't care much for Microsoft's "adoption" of XMPP. OBi... caught in the crossfire... oh, well.