You can block your number from caller identification (ID) units to help secure your privacy but, if you want to call a trusted person who does not pick up blocked calls, then unblocking may be required. There are two ways to unblock caller ID, per-call and per-line. Per-call requires that the number be unblocked from the phone itself. The per-line method will unblock calls from an entire phone line. Most toll-free numbers have special technology that allows people to see the phone number, even if the number is blocked. Without automatic number identification (ANI), there is no way for consumers to unblock incoming calls.
A per-call unblock will only unblock caller ID for the phone being used. To do this in the United States, you must pick up the phone and dial *67, or 1167 on a rotary phone. After that, you just dial the number regularly and this will unblock caller ID automatically. When the call is finished, the block will be reactivated. Outside the U.S., this type of unblocking requires the same technique but with different numbers.
Per-line unblocking is for businesses and buildings that use one line for several phones; this will only work if you own the entire line. To unblock caller ID over the line in the U.S., dial *82, or 1182 on rotary phones. As with the per-call unblock, this will only unblock the information for one call. If you do not own the entire line, which is common in many office buildings, you will be unable to perform this type of unblock. Again, a similar process but different numbers will perform the same function outside the U.S., and callers can check with their phone company to determine the particular number for their area.
If you call a toll-free number, chances are the business can find your number anyway, making it unnecessary to unblock caller ID. This is because businesses often use ANI technology, which allows them to screen calls and collect information even if you request that your name and number be blocked. This means you normally do not have to perform an unblock. If you are worried about businesses collecting your information, then it may be best not to call these numbers from your main or private line.
While ANI technology may make blocking your information from businesses nearly impossible, most people also will find it difficult to unblock incoming calls that have their name and numbers blocked. Unless you own ANI technology, you cannot unblock this information. You can request that the person call you back with the caller ID unblocked or you can ask for the caller’s name and number, but this may not be effective, depending on the caller.