Pick up the receiver on your AT&T landline phone and listen for a dial tone. Press *60 and press #. Wait for another dial tone.
Dial the first number, including the area code, that you wish to block on your AT&T landline. Press #.
Listen for another dial tone, dial the second number that you wish to block then press #. Repeat this step to block up to six numbers.
Hang up your phone. The phone numbers you entered are blocked.