AT&T CL81101 - Manual (Page 47)

Caller ID
42
Reasons for missing caller ID information
There are occasions when other information or no information shows for
various reasons:
On-screen message Reason
PRIVATE NUMBER
The caller prefers not to show the phone number.
PRIVATE NAME
The caller prefers not to show the name.
PRIVATE CALLER
The caller prefers not to show the phone number and name.
UNKNOWN NUMBER
Your telephone service provider cannot determine the
caller’s number.
UNKNOWN NAME
Your telephone service provider cannot determine the
caller’s name.
UNKNOWN CALLER
Your telephone service provider cannot determine the caller’s
name and telephone number.
Calls from other countries may also generate this message.