[Cisco Equipment and Related Hardware] Which Cisco collaboration component is an enterprise-grade, cloud-based PBX system that enables devices to register to the cloud?

Cisco Webex Calling is Cisco's cloud-native, enterprise-grade Private Branch Exchange (PBX) solution. It provides a complete business phone system delivered from the cloud, allowing devices like IP phones, soft clients, and mobile devices to register directly to the Webex cloud for call control services. This eliminates the need for on-premises PBX hardware and offers features like extension dialing, call forwarding, voicemail, and auto-attendants as a cloud-based service, integrating tightly with the broader Webex collaboration suite.

B. Cisco Hosted Collaboration Solution (HCS) is a platform for partners to build and deliver their own cloud collaboration services, not a direct-to-enterprise cloud PBX.
C. Cisco Webex Meetings is a service specifically for video conferencing and online meetings, not a comprehensive cloud-based phone system (PBX).
D. Cisco Webex Teams (now simply Webex) is the collaboration application for messaging and meetings; Webex Calling is the specific cloud PBX component within that ecosystem.

1. Cisco Systems, "Cisco Webex Calling Data Sheet," Document C78-742063-05, Page 2. The document states, "Webex Calling is a complete enterprise-grade cloud calling and team collaboration solution... It is a cloud-based phone system that is optimized for midsize to enterprise businesses."

2. Cisco Systems, "Webex Calling," Official Product Page. The overview describes it as "The cloud PBX that makes calling simple" and highlights its function as a "cloud phone system for businesses of all sizes."