In telecommunications, an acoustic coupler is an interface device for coupling electrical signals by acoustical means—usually into and out of a telephone.
Pulse dialing is a signaling technology in telecommunications in which a direct current local loop circuit is interrupted according to a defined coding system for each signal transmitted, usually a digit. This lends the method the often used name loop disconnect dialing. In the most common variant of pulse dialing, decadic dialing, each of the ten Arabic numerals are encoded in a sequence of up to ten pulses. The most common version decodes the digits 1 through 9, as one to nine pulses, respectively, and the digit 0 as ten pulses. Historically, the most common device to produce such pulse trains is the rotary dial of the telephone, lending the technology another name, rotary dialing.
Phreaking is a slang term coined to describe the activity of a culture of people who study, experiment with, or explore telecommunication systems, such as equipment and systems connected to public telephone networks. The term phreak is a sensational spelling of the word freak with the ph- from phone, and may also refer to the use of various audio frequencies to manipulate a phone system. Phreak, phreaker, or phone phreak are names used for and by individuals who participate in phreaking.
A payphone is typically a coin-operated public telephone, often located in a telephone booth or in high-traffic outdoor areas, with prepayment by inserting money or by billing a credit or debit card, or a telephone card. Prepaid calling cards also facilitate establishing a call by first calling the provided toll-free telephone number, entering the card account number and PIN, then the desired telephone number. An equipment usage fee may be charged as additional units, minutes or tariff fee to the collect/third-party, debit, credit, telephone or prepaid calling card when used at payphones. By agreement with the landlord, either the phone company pays rent for the location and keeps the revenue, or the landlord pays rent for the phone and shares the revenue.
A blue box is an electronic device that produces tones used to generate the in-band signaling tones formerly used within the North American long-distance telephone network to send line status and called number information over voice circuits. This allowed the user, referred to as a "phreaker", to surreptitiously place long-distance calls that would be billed to another number or dismissed entirely as an incomplete call. A number of similar "color boxes" were also created to control other aspects of the phone network.
John Thomas Draper, also known as Captain Crunch, Crunch, or Crunchman, is an American computer programmer and former phone phreak. He is a widely known figure within the computer programming world and the hacker and security community, and generally lives a nomadic lifestyle.
Black boxes were devices which, when attached to home phones, allowed all incoming calls to be received without charge to the caller.
A telephone booth, telephone kiosk, telephone call box, telephone box or public call box is a tiny structure furnished with a payphone and designed for a telephone user's convenience; usually the user steps into the booth and closes the booth door while using the payphone inside.
A telephone call is a connection over a telephone network between the called party and the calling party.
Phone fraud, or more generally communications fraud, is the use of telecommunications products or services with the intention of illegally acquiring money from, or failing to pay, a telecommunication company or its customers.
A clear box is an amplifier used by phreaks to use post-pay pay phones without paying. In some locations, especially rural areas in the United States and Canada, pay phones were configured for "post-pay" operation. In this mode, the handset microphone is muted until payment is made. The user of a post-pay pay phone would dial first, wait until the called party answered, and at that point the user would be prompted to insert the coins. Upon receiving the correct payment for the call, the pay phone would then connect the microphone and allow the caller to speak. An artifact of this scheme was that the called party usually heard the ACTS tones produced by the pay phone upon coin deposit.
In phone phreaking, a beige box is a device that is technically equivalent to a telephone company lineman's handset — a telephone fitted with alligator clips to attach it to a line.
2600 hertz (2600 Hz) is a frequency in hertz that was used by AT&T as a steady signal to mark currently unused long-distance telephone lines.
On analog telephone lines with special services, a flash or register-recall signal is used to control functions on the public telephone exchange, PBX or VoIP ATA.
A phreaking box is a device used by phone phreaks to perform various functions normally reserved for operators and other telephone company employees.
The off-hook tone is a telephony signal for alerting a user that the telephone has been left off-hook without use for an extended period, effectively disabling the telephone line.
Novation is an early modem manufacturer whose CAT series were popular in the early home computer market in the late 1970s and early 1980s, notably on the Apple II. The Hayes Smartmodem 300, introduced in 1981, helped kill off Novation and many other early modem companies over the next few years.
In Phreaking, the green box was a device whose function was to manipulate the coin collection mechanism of payphones. It employed three of the MF (multi-frequency) tones used in the blue box and could be viewed as a subset of that device.
Ringing is a telecommunication signal that causes a bell or other device to alert a telephone subscriber to an incoming telephone call. Historically, this entailed sending a high-voltage alternating current over the telephone line to a customer station which contained an electromagnetic bell. It is therefore also commonly referred to as power ringing, to distinguish it from another signal, audible ringing, or ringing tone, which is sent to the originating caller to indicate that the destination telephone is in fact ringing.
Echo suppression and echo cancellation are methods used in telephony to improve voice quality by preventing echo from being created or removing it after it is already present. In addition to improving subjective audio quality, echo suppression increases the capacity achieved through silence suppression by preventing echo from traveling across a telecommunications network. Echo suppressors were developed in the 1950s in response to the first use of satellites for telecommunications.
