WebRTC voice in Webex Contact Center is exposed to agents through the Desktop telephony option. Cisco's desktop profile documentation lists voice channel options, including Agent DN, Extension, and Desktop. The Desktop option allows the agent to sign in through the browser and use the Agent Desktop as the voice device rather than entering an external directory number or extension. Cisco's voice channel setup documentation also describes WebRTC-capable agents selecting Desktop under their telephony option so calls are routed to the Agent Desktop device. Browser is not a desktop profile voice option; it describes the client environment. Extension and Agent DN are traditional station credentials and would make the agent use a phone or configured number instead of browser-based WebRTC. Therefore, to enable agents to make and receive calls using WebRTC, the administrator must configure the Desktop option in the desktop profile. Reference: Cisco Help, Manage desktop profiles; Set up voice channels for Webex Contact Center.