What is the purpose of "CID" in the IPO system?

The purpose of "CID" in the IPO system is to refer to Call Identification, more commonly known as Caller ID. This feature provides users with the ability to see the identity of incoming callers, which can be crucial for call screening and managing communications efficiently. By displaying the caller's number (and often the name, if available), it allows users to decide whether to accept or decline a call based on the information presented.

This function enhances the user experience by adding a layer of information which helps in identifying potential spam or undesirable calls, thereby streamlining communication and reducing unwanted interruptions. Having such visibility over incoming calls ultimately contributes to improved user control and management of their phone system.