Define "trunk" in the context of the IPO.

In the context of the IPO (IP Office) system, a "trunk" refers to the connection between the IPO system and the public switched telephone network (PSTN). Trunks are essential for enabling voice communication between the internal users of an organization and external callers. They serve as the channels through which calls are established and managed, allowing for the infrastructure to connect different communication systems.

Trunks can support various types of connections including digital, analog, and VoIP communications, facilitating seamless integration with the outside telephone network. Understanding the function of trunks is crucial for configuring and managing an IPO system properly, as they determine how calls are routed and how many simultaneous calls can be handled.

The other options refer to different features of the IPO system, but they do not accurately represent the definition of a trunk. For instance, user extensions are individual telephone numbers assigned to users; voicemail management features pertain to handling messages left for users, and call recording methods focus on capturing conversations within the system. These are all important aspects of the IPO platform, but they do not encompass the specific meaning of "trunk" in this context.