How Does Caller ID Work: Privacy at Large
Caller ID (or also called CNID) in the United States, or Caller Display as it is known in England, costs about U.S. $2.00 or more per month in North America or less in other countries such as England. In Canada, the subscriber pays about U.S. $5.00 per month for the service (e.g., Province of Alberta) and receives the phone number of the caller as well as the name of the person calling (i.e., name of the subscriber or individual who is listed on the monthly phone bill sent to the address from where the call is originating).
In Canada, some provinces offer the individual telephone subscriber the option to block out the entire line of caller data, that is, the number is not revealed to any user, not even to the police when calling in an emergency. In contrast, British Telecom (BT) will block entire lines but only after their approval (e.g., for women shelters). Customers can block Caller Display/ID by dialing 141 before each call. However, BT claims that over 70% of customers “see no occasion where they might need” to use the 141 feature.
Alternate Number Display (AND) allows a number unique to the customer and different from one's phone number to show up on a called party's Caller ID box. The number cannot be called back and anyone who tries will get a message to the effect of, “The party you are trying to reach does not accept calls at this number.”