If you have Anonymous Call Rejection enabled (blocks callers who hide their Caller ID), you can usually turn that off by dialing *87 .
Best for: Traditional landlines provided by major carriers (AT&T, Verizon, CenturyLink, Frontier).
For digital landlines (e.g., Comcast Xfinity Voice, Ooma, Vonage), block lists are often managed at the account level.
*30# 123-456-7890#
Here's an example code to unblock a number on a landline using the *30# method:
Some modern cordless phones have a "Do Not Disturb" mode or "Call Screening" mode that silences all calls except those in your phonebook.
To unblock a number on a landline, the most common codes are for managing a blocked caller list and *82 for unblocking your own caller ID for outgoing calls . The exact method depends on whether the block is handled by your service provider or the physical handset itself. Common Dial Codes for Unblocking