Fact Sheet 9:
Wiretapping and Eavesdropping on Telephone Calls

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Copyright © 1993-2016
Privacy Rights Clearinghouse
Posted March 1993
Revised April 2016
  1. Introduction
  2. What can I do if I think my phone is tapped?
  3. Who can legally monitor phone conversations?
  4. Can digital telephone communications be monitored?
  5. Is it legal to tape record telephone calls?
  6. Are there products I can buy to find out if my phone is tapped?
  7. Are there other ways people may be listening to my conversations?
  8. What about pen registers and trap and trace devices?
  9. Who are the most common targets of electronic eavesdropping & wiretapping?
  10. Resources
  1. Introduction

    While relatively few legal wiretaps are authorized in the United States each year, improvements in technology have made it easier to illegally wiretap, record and eavesdrop on telephone conversations. People with sensitive jobs in business or government and those involved in high-stakes legal cases may have reason to be concerned about wiretapping and electronic eavesdropping.

    Wiretapping is any interception of a telephone transmission by accessing the telephone signal itself. Electronic eavesdropping is the use of an electronic transmitting or recording device to monitor conversations without the consent of the parties. Although many types of conversations may be subject to electronic eavesdropping, this fact sheet deals only with eavesdropping on telephone conversations.

    While this fact sheet deals only with wiretapping and eavesdropping on telephone conversations, wiretap laws are broader in scope.  Federal wiretap laws apply to oral, wire, and electronic communications.  However, the federal law does not currently regulate silent video communications, such as webcams or other video monitoring without an audio component.  A well-publicized case involving a school laptop in Lower Merion, PA highlights this limitation.  http://arstechnica.com/tech-policy/2010/03/school-laptop-spy-case-prompts-wiretap-act-rethink/.

    A total of 3,554 wiretaps were reported as authorized in 2014, with 1,279 authorized by federal judges and 2,275 authorized by state judges. The majority  involved drug cases.  Each tap lasted an average of 34 days.  Information gathered from the wiretaps led to 3544 arrests and 553 convictions.  http://www.uscourts.gov/statistics-reports/wiretap-report-2014.

  2. What can I do if I think my phone is tapped?

    If you discover that someone has intentionally intercepted your private phone conversations, you may be able to take legal action. If you or the phone company find an illegal tap, you should notify local law enforcement officials. In addition, you may want to consult an attorney.

    It is a federal crime to wiretap without court approval, unless one of the parties has given their prior consent. It is likewise a federal crime to use or disclose any information acquired by illegal wiretapping. Violations can result in imprisonment for not more than five years; fines up to $250,000 (up to $500,000 for organizations); in civil liability for damages, attorneys’ fees and possibly punitive damages; in disciplinary action against any attorneys involved; and in suppression of any derivative evidence.

    The government has been given narrowly confined authority to engage in electronic surveillance, conduct physical searches, install and use pen registers and trap and trace devices for law enforcement purposes under the Electronic Communications Privacy Act (18 U.S.C. 2510 et. seq.).  Over the years, Congress has amended ECPA, sometimes in the interests of greater privacy and sometimes in the interest of more effective law enforcement or intelligence gathering. For an in-depth discussion of ECPA, see the U.S. Department of Justice's Searching and Seizing Computers and Obtaining Electronic Evidence in Criminal Investigations.

    Many people think if they hear noises on the phone line, like clicks, static or voices, that the line is tapped. Most wiretapping devices emit no audible sounds. If you hear others talking on your phone, you may simply be experiencing "crosstalk," a common phone problem. If you hear crosstalk or other sounds, call your local phone company's repair service and ask it to investigate the problem. Cordless telephones also may pick up others' conversations. This can happen if you and a neighbor have cordless phones which are tuned to the same channel.

    If you think your phone line is wiretapped, call your local phone company. Most phone companies will inspect your lines for wiretap devices free of charge. If a tap is found, the phone company will check to see if it is authorized. The phone company will alert you if the wiretap is illegal. It will also notify law enforcement and remove the device. However, you will not be notified if the wiretap is legal, made by law enforcement and authorized by a court. However, once a legal wiretap has been discontinued, the court must notify the tapped party that the wiretapping has taken place. Normally, this notice must occur within 90 days of the wiretap termination. (18 USC 2518(8)(d)).

  3. Who can legally monitor phone conversations?

    Federal law enforcement officials may tap telephone lines only after showing "probable cause" of unlawful activity and obtaining a court order. This unlawful activity must involve certain specified violations. The court order must limit the surveillance to communications related to the unlawful activity and to a specific period of time, usually 30 days. (Electronic Communications Privacy Act, 18 USC 2516)

    Until recently, California wiretapping laws were much more restrictive, prohibiting all wiretaps without the consent of all parties to the conversation, except for investigations involving certain controlled substances violations (California Penal Code 629; 629.02; 631). However, as of January 1, 1996, the State Legislature amended this law to allow state law enforcement officials to obtain wiretaps in investigations involving murder, solicitation to commit murder, aggravated kidnapping, crimes involving bombings, and conspiracy to commit any of these offenses. This law is intended to bring California wiretapping law more in line with the federal law. (California Penal Code 629 et. seq.)

    Courts have held that the California law does not apply to wiretaps by federal agents authorized by a valid federal warrant. For example, federal agents may go to federal court and obtain a warrant to place a wiretap in California, even though state officials may be barred by state law from obtaining a wiretap under similar circumstances.

    Both federal and California law enforcement officials may eavesdrop on and record telephone conversations without a court order under the so-called "one party consent provision" (18 USC 2511(2)(s); California Penal Code 633). In other words, if state or federal authorities have the consent of one party to a conversation (such as a government informant), the conversation may be monitored. This provision applies only to eavesdropping by law enforcement officials.

    Telephone company employees may listen to your conversations when it is necessary to provide you with service, to inspect the telephone system, to monitor the quality of telephone service or to protect against service theft or harassment.

    Employers generally may monitor and even record their employees' phone conversations with few restrictions (18 USC 2511(2)(a); California Penal Code 631(b)). (See PRC fact sheet no. 7, "Employee Monitoring: Is There Privacy in the Workplace?")

  4. Can digital telephone communications be monitored?

    In 1994 Congress passed the Communications Assistance for Law Enforcement Act, also known as the Digital Telephony Act (18 USC 2510-2522). The Act's purpose is to provide law enforcement officials with assurance that they will be able to "tap" or have access to the content of any communications incorporating new digital technology. These digital transmissions include both voice communications transmitted in digital format as well as transmissions of text and data between computers using a modem.

    Traditionally, law enforcement agents accessed telephone communications by tapping the line and simply listening in on the conversation. However, digital communications services generally convert telephone conversations and other transmissions to a digital code that is impossible to "listen in" on. The Digital Telephony Act requires all telephone companies to make digital communications available to law enforcement officials in the same way that traditional voice transmissions are currently accessible.

    This law specifically states that it does not alter or expand the current ability of investigators to conduct a wiretap. It merely allows them to access digital communications in the same manner as voice communications once a legal wiretap has been authorized. Furthermore, telephone companies are not required to decrypt encrypted (i.e. scrambled) communications unless the telephone company itself provides the encryption service. Finally, the federal government must reimburse the telephone companies for many of the modifications necessary for compliance with the law.

    Users of Internet telephony services such as should note that most of these services are not subject to the provisions of the Digital Telephony Act.  The Act contains an exemption for "information services" (i.e., the Internet),  VoIP (voice over Internet protocol) services take many forms, from the peer-to-peer model used by Skype to others in which the path between the subscriber and the telephone central office is traditional telephony but Internet protocol (IP) communications are used throughout the remainder of the call's path. Most IP communications do not behave as telephone calls.  Peer-to-peer VoIP systems use a centralized mechanism to provide the communicating parties with each other's IP addresses but rely on the Internet for actual communication. Thus, there is no central point at which a wiretap could be authorized. 

    Stingrays are surveillance tools that can locate and track cell phones. They allow the police to pinpoint a cell phone’s location within a few yards by mimicking as cell phone towers.  Stingrays work by tricking phones in the area into transmitting their locations and identifying information. In doing so, they also capture information about all cell phones in an area, including people not suspected of a crime.  Stingrays can also capture emails, text messages and other data. Law enforcement agencies throughout the country possess Stingrays.   The ACLU’s Stingray Tracking Devices: Who's Got Them? provides more information.

  5. Is it legal to tape record telephone calls?

    The state and federal laws mentioned above deal primarily with wiretapping and eavesdropping by law enforcement officials. In addition to these laws, both the Federal Communications Commission (FCC) and the California Public Utilities Commission (CPUC) have acknowledged the importance of privacy in telephone conversations by placing additional restrictions on tape recording such conversations.

    California law does not allow tape recording of telephone calls unless all parties to the conversation consent (California Penal Code 632), or they are notified of the recording by a distinct "beep tone" warning (CPUC General Order 107-B(II)(A)(5)). However, tape recordings can legally be made if an individual or members of one's family are threatened with kidnapping, extortion, bribery or another felony involving violence. The person receiving the threats can make a tape recording without informing the other party (California Penal Code 633.5).  In March 2016, Wells Fargo Bank paid $8.5 million to settle claims that the bank failed to properly notify consumers that their phone calls were being recorded, in violation of California law.

    Federal law allows recording of phone calls and other electronic communications with the consent of at least one party to the call. A majority of the states and territories have adopted laws based on the federal standard. But 12 states, including California, require the consent of all parties to the call under most circumstances. These are are California, Connecticut, Florida, Illinois, Maryland, Massachusetts, Michigan, Montana, Nevada, New Hampshire, Pennsylvania, and Washington. For a state-by-state guide to taping laws, including a discussion of federal law and references to caselaw, see the Reporters Committee for Freedom of the Press guide, www.rcfp.org/taping/

    These laws and regulations often do not apply to law enforcement investigations, emergency situations or patently unlawful conversations. The FCC has acknowledged that these regulations are difficult to enforce, and violations are virtually impossible to detect. Consumers should not be lulled into a false sense of security that their call is private simply because there is no notice of recording.

    Furthermore, it is not always clear which law, state or federal, applies to specific situations. This depends on where the call originates, why the recording is being made and who places the call. To stay within the law, you may wish to refrain from taping calls you make, but be aware that in certain situations others may be recording your conversations with them.

    The California Supreme Court held in Kearney v. Salomon Smith Barney, Inc., 137 P.3d 914 (2006) that out-of-state businesses are prohibited from monitoring or recording their telephone calls with California residents, even if that conduct takes place in any of the states where only one party's consent is required to lawfully monitor or record a telephone call. Thus, California 's two-party consent law governs any calls between a company's location in a one-party consent state and customers located in California.

    In People v. Clark, 2014 IL 115776 (March 20, 2014), the Illinois Supreme Court struck down as unconstitutional the Illinois two-party consent law. For an analysis of the decision, see https://www.privacyassociation.org/privacy_tracker/post/spoiler_alert_illinois_may_no_longer_require_two_party_consent_but_californ

  6. Are there products I can buy to find out if my phone is tapped?

    No. Devices can be purchased which claim to detect phone taps. Let the buyer beware. Experts say there are no devices that can reliably detect any current wiretapping technology.

    To be successful, a "tap detector" must detect a change in the electrical characteristics of a telephone line, such as a voltage drop, or a change in the characteristics of signals that are transmitted over a telephone line. Most of the wiretapping techniques used today, whether authorized for law enforcement use or conducted illegally, do not produce changes in line or signal characteristics.  
    "Tap detectors" may be able to detect someone "listening in" by picking up an extension phone, and may be able to detect someone cutting a telephone line.  However, neither of these occurrences may be considered a "wiretap," strictly speaking, and neither of these occurrences is necessary in order for someone to connect a wiretap to your line.  Those with experience in telephone technology advise consumers to disregard the claims of companies that sell "tap detectors.

  7. Are there other ways people may be listening to my conversations?

    Yes. The determined eavesdropper will find a variety of sophisticated electronic surveillance and listening devices on the market. Also, radio scanners are available which can monitor cordless and cellular phone conversations, baby monitors and home intercom systems, especially older devices that use analog technology rather than digital signals.  

  8. What about pen registers and trap and trace devices?

    Certain devices, when attached to a phone line, allow the numbers of incoming or outgoing calls to be recorded. A "pen register" is a device which records numbers dialed out on the telephone line to which it is attached. A "trap and trace device" records the numbers from which any incoming calls are dialed.

    According to federal and California law, a court order must be obtained before these devices may be attached to a phone line (18 USC 3121; 69 California Attorney General Opinion 55). However, telephone companies may use these devices without a court order to protect against theft or fraudulent use of the telephone service, or to protect customers from harassment.

    These devices may only be used to obtain the number of the calling party.  Neither device is capable of recording the content of a conversation.   The use or installation of pen registers or trap and trace devices by anyone other than the telephone company, service provider, or those acting under judicial authority is a federal crime, punishable by imprisonment for not more than a year and/or a fine of not more than $100,000 ($200,000 for an organization). There is no accompanying exclusionary rule, however, and consequently a violation of section 3121 will not serve as a basis to suppress any resulting evidence.

  9. Who are the most common targets of electronic eavesdropping & wiretapping?

    If you are in a position where others might benefit from listening to your conversations, you may be a target of electronic eavesdropping or wiretapping. For example, if other companies could experience financial gain from hearing details about your work, you run a higher risk of being wiretapped or "bugged." People involved in controversial political activities and high-stakes legal proceedings are also at risk of being the target of illegal monitoring and eavesdropping.

    If you believe your phone conversations are being illegally monitored, you may want to consult an attorney and/or a private investigator. Be sure to check for references and proper licenses. Get all fees and conditions in writing before acquiring the assistance of a legal or investigative service.

    Since the terrorist attacks of September 11, 2001, many states have passed laws that expand their wiretapping authority. A comprehensive listing of state laws is available in the Congressional Research Service Report "Privacy: An Overview of Federal Statutes Governing Wiretapping and Electronic Eavesdropping" (October 9, 2012)

  10. Resources:

    Reporters Committee for Freedom of the Press

    For a 50-state listing of taping consent laws, "A Practical Guide to Taping Conversations" visit

    Congressional Research Service Report

    "Privacy: An Overview of Federal Statutes Governing Wiretapping and Electronic Eavesdropping" (October 9, 2012)


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