Participants dial in using a conference bridge number, which connects them to a common virtual meeting room that can be joined by people almost anywhere in the world. The meeting organizer may also call participants individually to add them to the conference line, a practice known as ad hoc conferencing.
In addition to a common dial-in number (usually provided via email or calendar invite), the conference call organizer may also supply a bridge URL. This link can connect callers to web conferencing services, through which they may use computer audio and possibly access other types of media and collaboration tools, including screen shares, video chats, and instant messaging platforms.
Conference calls have always been important for connecting employees with each other, and for helping a company reach external parties, such as its customers and business partners. However, their importance has greatly increased as more organizations have come to rely on telecommuters and mobile employees, while also expanding their geographical presences through branch offices. In addition, traditional conference calls are evolving to encompass more modern features, such as video conferencing, screen sharing, digital whiteboarding, and more.
Reference(s).. www.webex.com