Using Google Voice with ATAs and IP phones after 2023

[SteveInWA]

This is an updated (December 14, 2023) set of instructions to continue using consumer Google Voice with VoIP hardware devices (Analog Telephone Adapters or IP phones), after consumer Google Voice stops working directly on OBiTALK devices.  Of course, you do not need to follow these instructions (unless you wish) until your Google Voice number no longer works directly on OBiTALK devices.

These instructions require that you obtain inbound and outbound SIP VoIP telephone service from Callcentric.com (or another SIP ITSP of your choice).  This also provides E911 service and Caller ID Name (CNAM).

Although these instructions have been written for use with Callcentric, any other ITSP that offers open SIP credentials should work.  VoIP.ms will also work.  I have not, and do not receive any compensation from any VoIP ITSP for providing these instructions, and I don't care which service you use.

These instructions were written to use your existing Poly OBiTALK device.  If you don't have one, you can use any ATA or IP phone that supports standard SIP.  The Grandstream HT-801 is a good alternative if you only need one Service Provider account.

Note that any older instructions to use Callcentric with Google Voice, dating back to 2012, are obsolete; don't use those instructions.

• Assumptions:  you already have a working inbound Google Voice number, which you have previously configured on one or more  OBiTALK ATAs or IP phones, and you have intermediate-level technical skills to configure settings on websites.  In these instructions, we assume you have Google Voice setup on SP1.
• Callcentric (CC) is a no-frills SIP VoIP ITSP, which sells inbound calling and outbound calling separately (a la carte).  CC formerly had free inbound telephone numbers (DIDs) in NY; they now charge $1/month for those numbers, which include unlimited inbound calling with caller ID and CNAM.  See:  https://www.callcentric.com/dids/dollar_unlimited_phone_number
• They also offer outbound calling plans, with either a fixed number of minutes per month, or unlimited outbound calling.  Pick a plan that matches your calling needs:  https://www.callcentric.com/rate/plans/
• Sign up for a CC "Dollar Unlimited" DID (inbound), and sign up for an outbound calling plan (including  E911).  As a CC user, you now have a CC account, with a password to access the site.  You will then add services (inbound and outbound), and set up a SIP password for each DID added.  The SIP password does not have to be the same as the overall CC account password.  Make the password long and use random characters.
• Now that you have subscribed to CC services, use their dashboard to set up the extension you just added for inbound calls.  Write down the username (1777xxxxxxx) and the SIP password you just created.  Click on "Preferences" and then click on each of the gray tabs to edit your settings.  Enable CNAM, and set voicemail to answer after 35 seconds.
• Read and perform the instructions to verify your Google Voice number's caller ID with Callcentric:  https://www.callcentric.com/faq/31/218 Then, configure your Callcentric extension to use that caller ID for outbound calls.  This is known as "caller ID spoofing" and it is not illegal when you are the verified customer/user of that number.
• Sign into your device's configuration web page, via the device's IP address.  For example, you can follow Callcentric's instructions to locally configure your OBiTALK device, here: https://www.callcentric.com/support/device/obihai/obi202) If you are using a different ITSP and/or a different hardware product, they should provide you with ATA configuration information.  You'll see your Service Provider (SP1-SP4) configurations.  Assuming SP1 is Google Voice, click on the SP and delete its configuration. Next, set up your Callcentric SIP credentials to replace the Google Voice credentials you just deleted.  The proxy server is callcentric.com, and the proxy server port is 5060.  Use the 1777 number for the account number, and the SIP password.  Make some outbound test calls, and call the number from some other number, to confirm that it works. Set up your CC voicemail box (record a greeting).
• Sign into your Gmail account and go to the Google Voice settings page:  (https://voice.google.com/settings).  Find and delete the "OBiTALK Device".
• Go to the "Linked numbers" section, and click "+New linked number".  Add your new CC DID number (the actual telephone number, which typically begins with a New York State Area Code, NOT the 1777 number).  Complete the verification phone call.  Scroll down to Calls-->Inbound calls. There are green or gray toggle switches to the right of each device.  Toggle ON your CC phone number below that, in the Linked numbers section.
• Now, when someone calls your Google Voice inbound phone number, their call will be forwarded to your CC phone number, which you have enabled to ring on your OBiTALK device.
• Call your Google Voice number.  Your OBi-attached phone should ring and display the phone number and the name (or, if the name is unknown, it will display some generic information).
• When you place an outbound call, that call will route through Callcentric, but since you spoofed your Google Voice number earlier, the called party will see your Google Voice phone number.