Caller ID This feature allows the user to see the name and number of all incoming callers. How To Use: When a call comes in, wait a few seconds for the Caller ID unit to receive the information. The incoming caller's name and phone number will appear on the display screen. If you choose to accept the call, pick up the handset.  If you choose not to accept the call, no action is necessary. Note:  Before using this feature, users must subscribe to Caller ID and purchase a Caller ID electronic device.  When the letter "P" or the word "Private" appears on the screen, this indicates that the caller's phone number has been blocked.  When phrases like "unknown name," "unknown number," or "unavailable" appear on the screen, this is an indication that the incoming caller is in an area that does not support Caller ID services.