Cisco SPA 303g User Manual page 57

Blocking Anonymous Calls
Blocking anonymous calls prevents calls with unknown Caller ID from ringing your phone. (For
example, if a caller set his phone to not display Caller ID, the call is considered anonymous.)
These callers receive a busy signal or message.
Using the Setup button :
STEP 1 Press the Setup button.
STEP 2 Scroll to Preferences and press the select softkey.
STEP 3 Scroll to Block Anonymous Call and press the edit softkey.
STEP 4 Press the y/n softkey to choose yes.
STEP 5 Press the ok softkey.
STEP 6 Press the save softkey.
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