Fact Sheet # 19: Caller ID
Copyright 1996 - 1999. Utility Consumers' Action Network.
Revised August 1997.
This copyrighted document may be copied and distributed for educational
purposes only. The text of this document may not be altered without
express authorization of the Privacy Rights Clearinghouse. This fact
sheet should be used as an information source and not as legal advice.
PRC materials are designed primarily for California residents. Laws in
other states may vary. This publication was developed under the auspices
of the University of San Diego.
Privacy Rights Clearinghouse
1717 Kettner Ave. Suite 105
San Diego, CA 92101
Voice: (619) 298-3396
Fax: (619) 298-5681
Caller ID and My Privacy: What Do I Need to Know?
If you value your telephone privacy, a new service in California could
seriously affect your use of the phone: Caller ID. Beginning June 1, 1996,
when you make a phone call, your telephone number will be sent to the
person or office you are calling -- even if you have an unlisted number. If
those you call subscribe to Caller ID, they can read your phone number on a
display device and know who is calling before they pick up the phone.
The Caller ID device also captures the number in its memory for display at
a later time. So even if the person you call is not there to pick up the
phone, the Caller ID display device will capture the number for viewing
some other time. In addition, the time and date of the call are also
recorded and displayed.
What does Caller ID mean for your privacy? You will lose control over the
privacy of your phone number -- unless you take advantage of the free phone
number blocking options that are available to you.
How can I protect the privacy of my telephone number?
California's local telephone companies are required by law (Public
Utilities Code 2893) to offer free number blocking options to their
customers. There are two blocking options:
* If you choose Complete Blocking, your phone number will automatically
be blocked for each and every call that you make. When you call
someone who subscribes to Caller ID and has a display device next to
the phone, they will see the message "Private," "P" or "Anonymous"
instead of your phone number. (NOTE:: Calls to 800, 888, 900 numbers
and 911 cannot be blocked. See below.)
* If you choose Selective Blocking, your phone number is sent to the
parties you are calling. It appears on their display devices unless
you enter the code *67 before you dial the number (1167 on rotary
phones). With Selective Blocking, you must remember to enter the
blocking code for every call in which you want to protect your
privacy. You will hear a "stutter" dial tone after entering *67.
* In other states, Complete Blocking is called "Per Line" and Selective
Blocking is called "Per Call" Blocking.
The local phone company will assign you Selective Blocking unless you tell
them you want Complete Blocking. These blocking options are free of charge.
Make your choice known by calling your local phone company's toll- free
blocking selection number (see last page). You will receive a confirmation
letter from the phone company regarding the blocking option you selected.
Remember, unless you choose Complete Blocking, which is the strongest
option for people concerned about their privacy, you will automatically be
given Selective Blocking.
How do I choose which blocking option is best for me -- Complete or
Choosing Complete Blocking. Your decision to choose Selective or Complete
Blocking depends in large part on the risk you face if your phone number is
revealed to someone else. The higher the risk, the more likely you will
want to choose Complete Blocking. Your phone number will automatically be
blocked for every call you make when you select Complete Blocking. You may
unblock individual calls by pressing *82 before dialing the number (1182 on
Listed below are situations in which you might want to choose Complete
* You have an unlisted phone number. In other words, you have decided
that your telephone privacy is very important, and you are willing to
pay a monthly fee to the phone company to keep your number private.
You want Complete Blocking to prevent your number from being captured
by people and businesses you call.
* You are a victim of stalking, domestic violence or another form of
harassment and must block your phone number at all times.
* You are a member of a profession in which the privacy of your home
phone is important. You may at times need to make work-related calls
from home and want to ensure that the persons you call are not able to
reach you there. Some examples are: health care professionals,
especially mental health care providers; school teachers; law
enforcement officers; probation officers who may call parolees from
home; judges and other court officials; social workers; entertainers;
IRS and other government employees.
* You operate a domestic violence shelter or a safe home and must
safeguard the phone number and location of the residents.
* You want to report crimes to the police department's Crime Tips Line,
but want to remain anonymous.
* You have occasion to call a "help" hotline and want to remain
anonymous. Such hotlines include: suicide prevention, AIDS
information, immigration assistance, and mental health help lines.
Note: If you call 911-emergency or an 800 or 900 number, your phone
number cannot be blocked.
Here are some other situations where you might choose Complete Blocking:
* You do a lot of price shopping from home and do not want your phone
number collected for marketing purposes by the businesses you call.
* You have visitors to your home who might use your phone, such as
babysitters, your children's friends, relatives and other guests. You
don't want to risk revealing your number when phone calls are made, so
you choose Complete Blocking.
* You are helping a friend or relative who is vulnerable to
telemarketing scams like get-rich schemes, sweepstakes and prize
offers. To help them limit who is able to capture their phone number,
you suggest they select Complete Blocking.
* In general, you are someone who is very conscious of your privacy. You
want to take every precaution to safeguard it and therefore choose
Choosing Selective Blocking. If you experience few of the risks listed
above, you are more likely to choose Selective Blocking for your home
phone. Here are some situations where Selective Blocking makes sense:
* Most of the people you call from home are friends and family. Those
who subscribe to Caller ID don't like to pick up the phone unless they
see the phone number of the caller.
* You live alone, have few visitors, and are very careful about your use
of Selective Blocking. You are not likely to forget to enter the
Selective Blocking code *67 when you need to shield your number.
* You don't really know how you feel about phone number privacy, so you
choose Selective Blocking on a trial basis to see how it works for
you. You might change to Complete Blocking in the future if you find
that you prefer a higher degree of privacy.
Remember, Selective Blocking puts you at risk for the occasional slip-up --
by yourself, guests, the babysitter, or children. A single call where you
or a guest forget to enter the Selective Blocking code (*67) can leave you
open to unwanted marketing or, worse, a stalker or harasser. Post the
blocking sticker provided by the phone company on your phone so you and
others are reminded of the blocking option you have selected. When you
visit others and use their phone, always ask which blocking option they
How do I know if the person or business I am calling subscribes to Caller
There is no way to know if they have Caller ID. If you are concerned about
your phone number being captured, you must use one of the blocking options
Can numbers be captured even if the phone is not answered?
Yes, in most cases. Some display devices can save up to 100 incoming
numbers, whether or not the phone is answered. This can allow, for example,
a business to know who called after hours.
But the incoming phone number is not captured in every instance. If the
line is busy when someone tries to call, the Caller ID display device will
not capture the phone number. If the called party has Call Waiting and
someone tries to call, they will not yet be able to see the phone number of
the caller. But some time in the future, the phone company will allow the
calling number to be displayed in a call waiting situation, unless, of
course, that number is blocked.
My phone doesn't display any phone numbers. How can I see the phone numbers
of people calling me?
You can subscribe to the Caller ID service by paying a one-time start-up
fee and a monthly charge to the local phone company. (Call your phone
company's business office for cost information.) You must also buy a Caller
ID device or a specially equipped telephone that displays incoming
telephone numbers. Display devices are available from stores that sell
electronics products. They are also sold by the phone company. Prices start
What if I choose Complete Blocking, but some people won't answer the phone
unless they can see my number?
If you chosen Complete Blocking, you can selectively unblock your number
and allow it to be transmitted. Enter *82 each time you want your phone
number displayed (1182 on rotary phones).
What if I switch blocking options. Does it cost anything to change my mind?
Until the end of 1996, you may switch from one blocking option to another
without paying a service charge. Starting January 1997, you get one change
free and then a fee will be charged.
If I move and order new phone service, must I re-order Caller ID blocking?
To play it safe, tell the phone company which blocking option you want when
My home has more than one phone number. Do I have to choose a blocking
option for each one?
Yes. If you want Complete Blocking on each line, you will need to order it
for each phone number in your home. If you do not specify which blocking
option you want, you will be given Selective Blocking. Remember, blocking
is free no matter how many phones you have.
Can I block the phone number when I make calls from my cellular phone?
In most cases, no. At this time, there are only a few cellular phone
companies in California which have the technical capability to provide
Caller ID or the blocking options to their customers. Call your cellular
provider to find out. Ask if it uses "SS7," the telephone switching
technology that enables callers to block their phone numbers.
Can phone numbers be blocked from payphones?
It depends. Payphones operated by Pacific Bell and GTE allow Selective
Blocking (enter *67 before dialing the number). But independently operated
payphones might not allow blocking at this time. Look for the operator's
logo on the phone to determine ownership. By January 1, 1997, all payphones
must allow Selective Blocking. If you are a victim of stalking, domestic
violence or harassment and must prevent the phone number from being
released, look for a payphone that allows blocking (for now, Pacific Bell
and GTE payphones). When using payphones in other states, be sure to find
out the blocking options. (Note: Blocking is only necessary when you put
coins into the payphone. If the call is operator-assisted or involves a
calling or credit card, the payphone's number is not transmitted to the
recipient's phone; therefore, blocking is not needed.)
Will blocking work with modems? What about fax numbers?
If you do not want your modem's phone number to be transmitted, be sure to
use Complete or Selective Blocking. Fax numbers are a different story. A
federal regulation requires fax machines and fax cards in computers to
display the fax number on the document that is sent. (47 CFR 68.318) So
even if you block your fax number, it will still be printed on the
Does blocking work at my workplace? What about hotels and hospitals?
If your workplace uses Centrex (Pacific Bell) or Centranet (GTE), you are
able to block your phone number. But blocking is not likely to work if your
office uses a PBX system or if you are on a switchboard. The same is true
for hotels and hospitals with PBX systems. If it is important to block your
number from the office, a hotel or hospital -- for example if you are being
stalked -- be sure to find out if blocking will work. Listen for the
"stutter" dial tone after dialing *67, a sign that blocking works. You
might want to make test calls to friends who have Caller ID. When in doubt,
use a payphone and enter the *67 blocking code.
How can I find out what type of blocking has been selected on the phone I
am calling from?
For Pacific Bell, call (800) 386-0000. For GTE, call (800) 483-8707. When
you call this blocking verification number from the phone you want to use,
a recorded message will tell you which blocking method is in use for that
phone line. This number does not work in other states. So if you travel
outside of California, ask which blocking feature is available at the
phones you use.
When does blocking not work?
800,888 and 900 numbers. When you call an 800, 888 or 900 number, blocking
does not work. Your number will be transmitted to the called party, and can
be captured and displayed using a technology called Automatic Number
Identification (ANI). For example, many mail order companies with 800
numbers link their incoming phone service to a computer data base of all
customers' account information. When their phone rings, the data base
automatically retrieves customer information. Federal regulations place
restrictions on the use and sale of your phone number when you call an 800,
888 or 900 number. (47 CFR 64.1602) Your consent is required if your phone
number is reused or sold for purposes unrelated to your original call, for
example marketing purposes.
Calls to 911-emergency. When you call the 911-emergency number, your phone
number is transmitted even if you have Complete Blocking. The display
device used by emergency services usually shows not only your phone number,
but also your address. This enables police, fire and ambulance services to
locate you in case you are unable to provide the address.
What can marketers do with my telephone number?
If you call companies to gather information about products, prices or hours
of service, be aware that your telephone number could be captured unless
you block the number. Your phone number may have several uses:
* The company could simply use your number to make sales calls to you.
* The company might match your phone number against a data base
containing names and addresses, and then send you advertisements in
* Your number could be sold to companies that compile lists for
marketing purposes. The number would be matched against large data
bases containing names, addresses, and consumer profile information
(such as household income and ages). The enhanced mailing list
information would be sold to direct marketers.
When I call someone who has Caller ID, is my name shown on their display
device in addition to my phone number?
No. California phone companies only offer number display at this time. But
they plan to offer a name display feature in the future, if approved by the
California Public Utilities Commission.
However, devices can be bought at consumer electronics stores that allow
the purchaser to enter the names of callers into the device's memory. When
the phone detects the incoming Caller ID information, it alerts the device
to display the number as well as the name stored in memory. But only those
names which have been entered will show on the display screen. Other
devices can be programmed to speak the name and number of the incoming
caller out loud before the call is answered. Also, computer software for
"call management" can be purchased that allows an individual's phone to be
attached to a personal computer in order to keep track of incoming and
outgoing calls. The program displays and records the name and number of the
incoming caller, but only those names that have been entered into the
I have heard of a service called Anonymous Call Rejection. What does it do?
Some phone companies in other states provide Anonymous Call Rejection. This
programs the phone to reject calls from anyone who blocks their phone
number -- sometimes called "Block the Blocker." Callers hear an
announcement that the subscriber does not accept blocked calls. California
phone companies do not offer the service at this time, but may in the
Individuals can purchase devices in stores that do the same thing as
Anonymous Call Rejection. Instead of allowing the phone to ring, the caller
hears a recorded message stating that they must call again without blocking
Is Caller ID offered everywhere in the state of California?
Caller ID and other services like Call Trace and Call Screen are available
to most Californians. However, the telephone offices in some areas of the
state do not yet have the most up-to-date computer equipment and software
to handle Caller ID and other Custom Calling services. (The name of the
technology needed to provide Caller ID is Signal Switching 7, or SS7.)
If you are not sure if you live in an area with Caller ID and other Custom
Calling Services, ask your phone company's business office. Always read
your bill inserts for information on these services. No matter where you
live, if you want to be sure that your phone number is blocked, enter *67,
the Selective Blocking code, before dialing the number. (Remember, Caller
ID will be implemented in California June 1, 1996.)
Is Caller ID available in other states?
As of June 1996, Caller ID is available in all 50 states. California was
the last state to implement Caller ID. (But California was the first to
require free number blocking, legislatively in 1989.) In other states,
between 6% and 12% of residential households have subscribed to Caller ID.
From 25% to 40% of businesses have subscribed.
When you travel to other states, keep in mind that Complete Blocking is not
available everywhere. If you need to block your phone number while you are
on the road, play it safe by entering *67 before you dial the number. This
blocking code works in all 50 states.
What happens when I call someone long distance in another state?
Caller ID crosses state lines, and so do the blocking codes. When you make
long distance calls, your phone number is sent to the party you are
calling, the same as if you're calling someone nearby. Unless you use
Complete or Selective Blocking, your phone number will appear on Caller ID
display devices in other states. (In a few areas Caller ID technology is
not yet installed. People who get calls from places where Caller ID is not
yet available will see the message "out of area" on their display devices.)
Could Caller ID contribute to "redlining?"
Consumer advocates are concerned that Caller ID could be used to
discriminate against consumers with a practice called "redlining." For
example, a pizza delivery company or taxi service might avoid serving high-
crime areas. They would determine such areas by looking at the first three
digits of the phone number after the area code (the "exchange"). If you
become aware that a company is practicing redlining, contact the California
Public Utilities Commission. Please also alert the Privacy Rights
Is Caller ID useful in stopping harassing phone calls?
In many situations, no. Most harassers will block their phone numbers or
call from payphones. However, Caller ID can be used by people receiving
harassing calls to decide whether to answer calls. They can choose not to
pick up calls marked "private" or numbers they don't recognize.
Are there other ways to stop harassing phone calls?
Yes. Other services are available from the phone company to help you deal
with harassing callers. (Fees are charged.) There are also products
available in stores for blocking harassing calls.
Call Trace. The phone company's Call Trace service allows you to have the
phone number of the harassing caller identified, whether or not the caller
blocks the number. When you activate the Call Trace code (*57) immediately
following the harassing call, the caller's phone number is recorded by the
phone company. The phone number is not given to you, however. You will be
asked by the phone company to sign an authorization form before the
harasser's phone number is turned over to law enforcement for further
To order the Call Trace service, you must pay a start-up fee. For Pacific
Bell, there is no monthly service charge. Instead, you pay $5 each time you
use the feature with a monthly maximum of $25. For GTE, you pay a monthly
charge of $5 for an unlimited number of traces.
Call Trap. The traditional way that telephone companies have tracked down
the phone numbers of harassers in the past is a free service called a Trap.
When you report repeated obscene or harassing calls to the phone company's
Annoyance Call Bureau, they can decide to put a Trap on the line. You will
be asked to keep a log of the dates and exact times that you get harassing
calls. The Trap will be kept on your line for a specific period of time,
usually two weeks. When you give your log to the phone company, they will
check it against their records to determine the phone number(s) of the
harasser. This information is given to law enforcement.
Choosing between Trap and Trace. Instead of choosing Call Trap, the
Annoyance Call Bureau might decide to provide you Call Trace at no charge
for a two- to three-week period. However, there are parts of the state
where Call Trace is not yet available, so a Trap is the only method for
tracking down the numbers of harassing callers.
Call Screen (called Call Block by GTE). This service allows you to block
calls from up to 12 numbers. You can also block the number which just
called you, even though you may not know the actual number. Your phone will
not ring when you are called from one of these numbers. Instead, the caller
will get the message, "The party you are calling is not accepting this
call." There is both a start-up fee and monthly charge for this service.
Be aware that if you use Call Screen to reject calls from a harasser, that
person is likely to go to another phone or a telephone booth so the call
can be made from a number that is not blocked.
Selective Call Acceptance (GTE service only). You can program your phone
line to accept up to 12 phone numbers, those callers who you most want to
talk to. All other callers, including the harasser, hear a message that you
are not accepting calls now. You can turn this service on or off at any
Call Return. This feature lets you automatically redial the last call you
received. You must pay a start-up fee and monthly charges. Call Return is
of limited use for harassing calls, however. When you enter the Call Return
code *69 to dial the most recent call, you are not able to learn the number
of the caller. (In some states, a voice message gives that number to you
when you enter *69, but not in California.) If the returned call is a toll
call, the last four digits of the number do not appear on your phone bill.
But you will have to pay the toll charge. Another limitation is that Call
Return only works in the local service area. (See the "Customer Guide"
section of your White Pages for a map of California's local service areas.)
Special devices. Special call screening devices known as "inbound call
blockers" can be purchased that allow you to reject certain calls. Only
those callers who enter a special numeric code onto their touchtone phones
are able to ring through to your number. Victims of harassing calls have
reported these devices to be very effective. However, you must be sure to
give the code to everyone you want to talk to. You could miss important
calls from unexpected sources, including emergency services. These and
other types of call screening devices can be purchased at many stores that
sell consumer electronics devices.
Don't forget that the most effective call screening device for harassers
may be the answering machine, an answering service, or voice mail. (For
additional tips, see PRC fact sheet 3, "How to Put an End to Unwanted or
Harassing Calls," and fact sheet 14, "Are You Being Stalked? Tips for
The future of Caller ID
The Caller ID service offered by the phone company today is certain to
change in the future. New features will be offered. Some may enhance your
privacy; others may harm it.
Be sure to read your monthly telephone bill inserts to become informed
about any new developments with Caller ID. Take advantage of opportunities
to express your opinions to the California Public Utilities Commission, the
state agency which regulates the local phone companies.
For more information
Phone company numbers to call to order blocking.
* Pacific Bell (800) 298-5000
* GTE (800) 884-8739
Numbers to call to check the blocking option in use on the phone you are
* Pacific Bell: (800) 386-0000
* GTE: (800) 483-8707
Phone company numbers to call to get information about other Custom Calling
* Pacific Bell: (800) 21-GUIDE or (800) 214-8433
* GTE: (800) SMARTCALL or (800) 762-7822
Complaints about Caller ID can be made to:
* California Public Utilities Commission
Consumer Affairs Branch
505 Van Ness Ave.
San Francisco, CA 94102.
Phone: (800) 649-7570
This fact sheet is available in Spanish, Chinese, Vietnamese and Korean
from the Privacy Rights Clearinghouse (these languages available May 1996).
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