page_title: Telephone tapping
section_title: Non-official use
hierarchical_section_title: Telephone tapping / Methods / Non-official use
caption_attribution_description: English: Picture of a telephone recording adapter for use in its related articles. Taken by me using Nokia N-70 w/ help of magnifying glass and White LED camping light.
context_page_description: Telephone tapping is the monitoring of telephone and Internet-based conversations by a third party, often by covert means. The wire tap received its name because, historically, the monitoring connection was an actual electrical tap on the telephone line. Legal wiretapping by a government agency is also called lawful interception. Passive wiretapping monitors or records the traffic, while active wiretapping alters or otherwise affects it.
context_section_description: Conversations can be recorded or monitored unofficially, either by tapping by a third party without the knowledge of the parties to the conversation, or recorded by one of the parties. This may or may not be illegal, according to the circumstances and the jurisdiction.
  There are a number of ways to monitor telephone conversations. One of the parties may record the conversation, either on a tape or solid-state recording device, or on a computer running call recording software. The recording, whether overt or covert, may be started manually, automatically by detecting sound on the line (VOX), or automatically whenever the phone is off the hook.
  using an inductive coil tap (telephone pickup coil) attached to the handset or near the base of the telephone, picking up the stray field of the telephone's hybrid;
  fitting an in-line tap, as discussed below, with a recording output;
  using an in-ear microphone while holding the telephone to the ear normally; this picks up both ends of the conversation without too much disparity between the volumes
  more crudely and with lower quality, simply using a speakerphone and recording with a normal microphone
  The conversation may be monitored (listened to or recorded) covertly by a third party by using an induction coil or a direct electrical connection to the line using a beige box. An induction coil is usually placed underneath the base of a telephone or on the back of a telephone handset to pick up the signal inductively. An electrical connection can be made anywhere in the telephone system, and need not be in the same premises as the telephone. Some apparatus may require occasional access to replace batteries or tapes. Poorly designed tapping or transmitting equipment can cause interference audible to users of the telephone.
  The tapped signal may either be recorded at the site of the tap or transmitted by radio or over the telephone wires. As of 2007 state-of-the-art equipment operates in the 30–300 GHz range to keep up with telephone technology compared to the 772 kHz systems used in the past. The transmitter may be powered from the line to be maintenance-free, and only transmits when a call is in progress. These devices are low-powered as not much power can be drawn from the line, but a state-of-the-art receiver could be located as far away as ten kilometers under ideal conditions, though usually located much closer. Research has shown that a satellite can be used to receive terrestrial transmissions with a power of a few milliwatts. Any sort of radio transmitter whose presence is suspected is detectable with suitable equipment.
  Conversation on many early cordless telephones could be picked up with a simple radio scanner or sometimes even a domestic radio. Widespread digital spread spectrum technology and encryption has made eavesdropping increasingly difficult.
  A problem with recording a telephone conversation is that the recorded volume of the two speakers may be very different. A simple tap will have this problem. An in-ear microphone, while involving an additional distorting step by converting the electrical signal to sound and back again, in practice gives better-matched volume. Dedicated, and relatively expensive, telephone recording equipment equalizes the sound at both ends from a direct tap much better.
caption: A telephone recording adapter (in-line tap). The phone jack connects to the wall socket while the phone being monitored is connected to the adapter's socket. The audio plug connects to the recording device (computer, tape recorder, etc.).
exif: {"Image Make": "Nokia", "Image Model": "N70-1", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "138", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "590", "Thumbnail JPEGInterchangeFormatLength": "7876", "EXIF ExposureTime": "59213/1000000", "EXIF FNumber": "16/5", "EXIF ISOSpeedRatings": "320", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2007:12:10 21:14:32", "EXIF DateTimeDigitized": "2007:12:10 21:14:32", "EXIF ComponentsConfiguration": "YCbCr", "EXIF ShutterSpeedValue": "4077/1000", "EXIF ApertureValue": "84/25", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "9/2", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1188", "EXIF ExifImageLength": "1464", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "High gain up"}