Most cell phones have caller identification (caller ID) services built in that allow individuals to see the phone number of any person who calls. For people who wish to remain anonymous, caller ID can seem like an infringement of privacy. Luckily for them, there are a few simple methods for blocking a number so that it appears as "Unavailable" on the receiver's caller ID.
Changing Your Cell Phone Settings
Most new cell phones have privacy settings that can be changed to make your phone number appear as "Unavailable" on the caller ID of other phones. You can navigate to the menu of your cell phone to find the privacy or network settings. Within this category is a Caller ID subcategory or an option that reads "Show/Hide My Number." Hiding your number prevents people you call from being able to see your cell phone number on their caller ID. Testing whether or not the option was implemented successfully can be accomplished by calling a friend's or family member's cell phone. Cell phone user's manuals provide specific directions for changing privacy and caller ID settings.
Using a Caller ID Blocking Service
If you have an older cell phone or one that simply does not have an option to make your number appear as "Unavailable," you can use a caller ID blocking service to accomplish the same result. It is used by pressing the star or asterisk symbol () then "67" before the phone number is dialed. For example, when dialing the number 1-800-555-5555, you would dial 67-1-800-555-5555 to block your number from the phone that you call. This caller ID blocking service can cost a few cents per use for certain service providers and is free for others. Your cell phone service provider can tell you whether or not *67 costs anything for you to use.