Open for Google Voice

Google Voice for Workspace remains the phone system. Users, ring groups, and the auto-attendant tree all stay in the Google Admin Console. Open joins as a destination — either via SIP Link (Google's BYOC pairing) or via auto-attendant call forwarding to an Open-owned number.

On Workspace Standard or Premier with SIP Link, the cleanest pattern is to add Open as a SIP destination reachable through your SIP Link partner. Inbound calls hit Google Voice, follow your auto-attendant or ring-group routing, and at the point you want AI to take over they get sent to Open over SIP. The AI picks up and the rest of the conversation runs over standard SIP/RTP.

On plans without SIP Link, the integration uses call forwarding from the auto-attendant to an Open-owned phone number. You provision an Open inbound number, attach it as the forwarding destination on the auto-attendant branch you want AI'd, and Google Voice routes matching calls to it. AI answers, then warm-transfers back to a number on your Google Voice ring group for human handoff.

What the AI does on the call: it greets, listens, reasons over your knowledge base and connected tools (Google Workspace contacts, calendar, Sheets, plus CRM/ticketing integrations), and acts. When the AI needs a human, it warm-transfers back via SIP REFER (SIP Link path) or PSTN bridge (forwarding path) with the live transcript attached.

Google Voice consumer (free Google Voice numbers tied to a Google account) is not a supported integration target — there's no admin path to forward to external destinations or add SIP routing. For business AI, Google Workspace Voice is the real option.