Calling line identification (CLID), commonly known as caller ID is one of the most useful inventions in telecommunication. This is a telephone service available for both analog as well as digital phones. It allows the user to see the caller's telephone number, before answering the call. This invention proved very useful to curb prank callers and also provided an evidence in certain criminal cases. However, some callers perceived it as an intrusion upon their privacy. As a result, people started looking for evasive techniques to retain their privacy. Naturally, various methods to block caller ID came into practice. If you don't have any nefarious intentions, and want to block your number for privacy issues only, then you may use any of the following methods of blocking it.
Blocking Caller ID
This is the most popular technique to block caller ID. You may choose to permanently block your number or you may go for temporary blocking. This technique works by dialing certain codes before you dial the recipient's number. For instance, if you are residing in US or Canada, then you have to dial *67 before you dial the intended number. Alternatively, you may also dial #31#, if you are calling from the US. Residents of UK should dial 141 to block their phone numbers from appearing on CLID. Your recipient's instrument will show a message 'caller ID blocked'.
Service from Phone Company
You may request your telephone service provider to provide the caller ID blocking service, either on temporary basis or permanently. Your company might charge you for this service. However, there are certain companies that provide this service for free. Once you start availing the service, your telephone number will be masked by default. However, there might be times when you would like to reveal your number to certain recipient's, in such cases, you can discontinue the blocking service by dialing *82.
Third Party Calls
There are certain services that route the call from a third party. In this case, the caller ID device cannot trace your original number. The examples of such services are prepaid phone cards, or using Skype from your computer.
Some cell phone service companies offer you an option of calling a person via voicemail. While using this service, you should wait for a call option to appear. When it does, enter the recipient's number and make a normal call. Since, this technique uses the voicemail service activated by the recipient, you are essentially using their own line, which appears as blocked ID and masks your number.
One of the main objectives behind inventing caller ID was to avoid annoying telemarketing calls. However, telemarketers have come up with newer means to pester their potential customers. Spoofing service is a technique that masks your original number, and shows it as a different number on your recipient's caller ID. This is a great technique to fool the poor unsuspecting users. You can avail this service by paying a certain amount to the service provider company. Then, you get a personal identification number (PIN), which allows you to make calls for a certain amount of time. Then, you can dial the number given to you by the company and enter your PIN. Next, you can dial the number of your recipient, and lastly, the number you wish to appear as your own. At times, web based interface may be used to generate spoof calls.
The above content should be used judiciously to block caller ID, these methods have been invented to protect one's privacy and not for harassing people. Encouraging malicious and unlawful practices is not the intent of this article. Therefore, it is strongly recommended that you check your local cyber laws before going for any caller ID blocking methods.