If you want to spend five minutes on this subject, read my short FAQ. If you're fanatically interested in the subject, a web search will provide you endless reading. If you're just a normally curious person who loves to pick (and win) arguments at parties, read on...
Ordinarily, when you originate a telephone call, your phone number (and, in some locations, your name) is also transmitted so that the called party can know who is calling before answering. When this wonderful feature, known as Caller ID (CID) was proposed in California, the nay-sayers came out of the woodwork, inundating Public Utilities Commission with complaints that Caller-ID constituted a violation of their privacy. Lost in this hullabaloo, however, was the observation that Caller-ID per se does not deprive the calling party of privacy, but rather deprives them of anonymity--an important distinction.
Those opposed to Caller-ID objected to the revealing of their phone numbers when calling business and companies. Their fear, as I understand it, is that businesses will capture their phone number in an amorphous database and use it for nefarious purposes. Reasonable people can disagree about whether companies would put Caller-ID to this use (they probably would), and even on whether this is a bad thing (it probably isn't). Lost in the scuffle, however, was a reasoned discussion of how selective Caller-ID blocking could protect callers from such predatory businesses, yet provide a mechanism for the caller to politely send his number when making ordinary calls to friends or acquaintances.
The Federal Communications Commission (FCC) watched with interest all the various tug-of-wars, particularly California's. The FCC finally decided to take federal action because of all the turf wars going on between local and long distance phone companies, consumers and state regulators. The FCC issued a ruling in April, 1994 that established a national standard for Caller ID. The FCC also ordered all local and long distance phone companies equipped with the requisite equipment to exchange Caller-ID.
To allow customers to opt out of this feature, the FCC mandated that all users be provide at no charge a standard mechanism to defeat the sending of Caller-ID on a "selective" (i.e., call-by-call) basis. In other words, each subscriber chooses whether he wants Caller-ID to be completely blocked or selectively blocked. Users who chose Selective Blocking can block Caller-ID for the next call by prefixing *67 to a phone number; similarly, users who chose Complete Blocking can unblock Caller-ID for the next call by prefixing *82 to a phone number.
This sounds like a reasonable solution, doesn't it? Not so fast! The FCC left it for state regulators to decided whether to permit "Complete Blocking" (i.e, per-line) in their state. With Complete Blocking, the sending of Caller-ID is not under the caller's control--it is never sent. Under strong lobbing by consumer advocacy groups, California's regulators not only opted to require the per-line (Complete) blocking option in California, they required the phone companies to slant their sales pitch in favor of per-line (Complete) over per-call (Selective) blocking. Many California consumers fell for the specious logic put forth by the consumer groups: that Complete Blocking maintains the status quo. This is incorrect, though, because Caller-ID actually identifies all blocked calls as a "private" or "anonymous" call. While this approach shortstops the nosy business, it also has the effect of preventing your friend or relative who has opted for the Caller ID service to screen calls coming into their homes.
The upshot of these "privacy wars" was that Caller-ID was not implemented in California until July, 1996--the last state to do so. If you wish, you can read SBC's explanation of Caller-ID.
With the rapid increase of telemarketing (a euphemism for "phone-to-phone salesmanship"), the hours 7:30am-9:00am and 6pm-10pm has become a shooting-gallery for "courtesy" calls (courtesy?) and all manner of unsolicited solicitations.
What's more, the longer you've owned your phone number--we've had ours for 27 years--the more calling lists you're likely to be on and the more of these annoying phone calls you receive. In the war against telemarketing, Caller ID is powerful weaponry. Why? Because most telemarketing boiler rooms and corporate naggers hide behind big, so-far-FCC-exempt, large phone systems, which don't transmit Caller-ID.
The Caller-ID approach to telephone management has some pretty serious flaws, both operationally and philosophically. Operationally, the service itself is expensive ($6.50 per month) as are the special hardware devices necessary to detect, decode, and display the caller's phone number. In addition, who wants to program a device (and keep that programming up to date) with a list of all the numbers you wish to talk to? And, of course, it is impossible to compose a list of everyone you don't wish to talk to, for such a list is practically infinite. Philosophically, Caller-ID makes the assumption that anyone whose phone number is unknown is someone you don't want to talk to. I personally don't like the xenophobic, slightly hermitic implications of this philosophy.
So, what's a body to do? You don't want to seal yourself off from friends and that occasional serendipitous phone call, but neither do you wish to be tormented by endless sales pitches and harangues by strangers. To solve this dilemma, I conceived of an integrated telephone, answering machine, and Caller-ID decoder. It would work as follows: callers with their Caller-ID blocked would not cause my phone to ring; instead they would hear a polite message explaining that I don't accept anonymous calls, and asking them to hang up and call back with the *82 prefixed to my phone number. In all other ways, the device would function as an ordinary answering machine.
A few weeks later, I learned of a new service by Pacific Bell (now SBC): Anonymous Call Rejection (ACR), which provides most of the functionality of the Caller-ID service and equipment, but costs only $2 per month. Using this service, a blocked call never reaches your telephone, but is intercepted by the phone company. The caller hears the following message:
"The party you called does not accept calls from blocked numbers. To reveal your number on this call, hang up, pickup the receiver, dial *82 then the number or 1182 from rotary phones. To prevent the display of your number use a pay phone or for a charge, call the operator."
While this announcement is terse and is recited very rapidly, it gets the job done. I'd estimate that our telemarketing calls have decreased by 90%. And while our friends were a bit disconcerted by it at first, for the most part they've come to terms with it.
I predict that Anonymous Call Rejection will become increasingly popular as word about it spreads. So, what should you do about all of this? I recommend adopting my philosophy: I'll show you mine if you'll show me yours! That is, if you have Complete Blocking--change it to Selective Blocking by calling 1-800-310-2355. There's no charge for this change. Having now exposed your number to the outside world, you need to guard against telemarketers by subscribing to Anonymous Call Rejection. I think you'll find this greatly simplifies the phone wars. Oh, by the way: subscribing to Anonymous Call Rejection and Complete Blocking guarantees that you will go to hell.