Sharp FO-880 Operation Manual page 97

4
Enter the full number you want to
block (max. of 20 digits).
5
Press the START/MEMORY key.
6
Return to Step 3 to enter (or clear)
another number, or press STOP to exit.
Blocking Reception of Unwanted Faxes
5 5 5
START/MEMORY
Step 3 or
1 2
3 4
(Example)
STOP
95