Panasonic KX-TC1851ALB Operating Instructions Manual page 25

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≥If a phone number is not displayed in the caller information, you cannot call back
that caller.
For New Zealand Users:
Your telephone service provider may charge you for a local call
when it is dialled with an area code prefix. If the charge for local call
is unacceptable, only the 7-digits of the local number should be
dialled from your telephone. Do not dial the "0" prefix or the area
code digit.
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