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Call Termination: Google Voice and Callcentric


Early 2022 the 833-NYC-MESH number was parked at NumberBarn until further research could be done on how to implement the number. In the meantime the Google for Nonprofits platform was used to get access to Google Voice for a preliminary IVR/auto-attendant solution for routing calls to particular Google Workspace users and email to Slack for voicemail.

Google Voice does not support porting-in toll-free numbers for terminating calls and thus an external provider must be used in conjunction with the 833-NYC-MESH number. Currently, Callcentric has been chosen as our SIP provider due to widespread adoption, low rates, and positive testimonial, though the features it provides can all be replicated using a SIP Trunk->IP PBX architecture.


The 833-NYC-MESH number is ported into Callcentric for inbound termination and outbound origination. Currently, the Call Treatments feature forwards all incoming calls to the Google Voice auto-attendant "Hotline - Main", though the beta IVR setup through Callcentric's internal portal is partially configured and can be switched over at any time for testing.

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After a rigorous cost-benefit analysis on the plans available through Callcentric compared to the cost of expanding the Google Voice service further, multiple scenarios were drawn out to compare the price per a fixed number of minutes per month.

This Google Sheet has the pricing for pay-as-you-go inbound and outbound calls (which results in a double charge due to the forward to the Google Voice Hotline Root is billed as well as the inbound to the toll-free number), the 500-minute package for outbound calls (to eliminate the double charge for forwarding to Google Voice and regular outbound calls, and eliminating forward to Google Voice all together and handle calls entirely internally.

Based on findings after testing the plans and billing behavior in Callcentric, it was determined that the 500-minute package makes the most sense for preserving Google Voice auto-attendant integration while saving a small amount of funds, while switching entirely to Callcentric for IVR handling is most cost-effective, though there are drawbacks to needing to manually configure SIP endpoints for all users (though those endpoints are more flexibly configured than Google Voice Users.

Callcentric Cost Calculator - Google Sheets