A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from Greek: τῆλε and φωνή, together meaning distant voice. A common short form of the term is phone, which came into use almost immediately after the first patent was issued.
In telephony, ringdown is a method of signaling an operator in which telephone ringing current is sent over the line to operate a lamp or cause the operation of a self-locking relay known as a drop.
Caller identification is a telephone service, available in analog and digital telephone systems, including voice over IP (VoIP), that transmits a caller's telephone number to the called party's telephone equipment when the call is being set up. The caller ID service may include the transmission of a name associated with the calling telephone number, in a service called Calling Name Presentation (CNAM). The service was first defined in 1993 in International Telecommunication Union—Telecommunication Standardization Sector (ITU-T) Recommendation Q.731.3.
Wardialing or war dialing is a technique to automatically scan a list of telephone numbers, usually dialing every number in a local area code to search for modems, computers, bulletin board systems and fax machines. Hackers use the resulting lists for various purposes: hobbyists for exploration, and crackers—malicious hackers who specialize in breaching computer security—for guessing user accounts, or locating modems that might provide an entry-point into computer or other electronic systems. It may also be used by security personnel, for example, to detect unauthorized devices, such as modems or faxes, on a company's telephone network.
A ringtone or ring tone is the sound made by a telephone to indicate an incoming call or text message. Not literally a tone nor an actual (bell-like) ring anymore, the term is most often used today to refer to customizable sounds used on mobile phones.
The answering machine, answerphone or message machine, also known as telephone messaging machine in the UK and some Commonwealth countries, ansaphone or ansafone, or telephone answering device (TAD), is used for answering telephones and recording callers' messages. If a phone rings a predetermined number of times by the phone's owner, and nobody is present to answer the incoming call, the answering machine will activate and play either a generic announcement or the voice of the person being called announcing that nobody is able to come to the phone at the moment. Following the announcement is a beeping tone which prompts the caller to record his or her message after the tone concludes.
A telephone call is a connection over a telephone network between the called party and the calling party.
A conference call is a telephone call in which someone talks to several people at the same time. The conference call may be designed to allow the called party to participate during the call or set up so that the called party merely listens into the call and cannot speak. It is sometimes called ATC.
Call forwarding, or call diversion, is a telephony feature of some telephone switching systems which redirects a telephone call to another destination, which may be, for example, a mobile or another telephone number where the desired called party is available. Call forwarding was invented by Ernest J. Bonanno. In North America, the forwarded line usually rings once to remind the customer using call forwarding that the call is being redirected. More consistently, the forwarded line indicates its condition by stutter dial tone. Call forwarding typically can redirect incoming calls to any other domestic telephone number, but the owner of the forwarded line must pay any toll charges for forwarded calls. Call forwarding is often enabled by dialing *72 followed by the telephone number to which calls should be forwarded. Once someone answers, call forwarding is in effect. If no one answers or the line is busy, the dialing sequence must be repeated to effect call forwarding. Call forwarding is disabled by dialing *73. This feature requires a subscription from the telephone company. Also available in some areas is Remote Access to call forwarding, which permit the control over call forwarding from telephones other than the subscriber's telephone. VOIP and cable telephone systems also often allow call forwarding to be set up and directed via their web portals.
A business telephone system is a multiline telephone system typically used in business environments, encompassing systems ranging in technology from the key telephone system (KTS) to the private branch exchange (PBX).
An intercom, talkback or doorphone is a stand-alone voice communications system for use within a building or small collection of buildings, functioning independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles. Intercoms can incorporate connections to public address loudspeaker systems, walkie talkies, telephones, and to other intercom systems. Some intercom systems incorporate control of devices such as signal lights and door latches.
Direct inward dialling (DID), also called direct dial-in (DDI) in Europe and Oceania, is a telecommunication service offered by telephone companies to subscribers who operate a private branch exchange (PBX) system. The feature provides service for multiple telephone numbers over one or more analog or digital physical circuits to the PBX, and transmits the dialed telephone number to the PBX so that a PBX extension is directly accessible for an outside caller, possibly by-passing an auto-attendant.
Internet fax, e-fax, or online fax is the use of the internet and internet protocols to send a fax (facsimile), rather than using a standard telephone connection and a fax machine. A distinguishing feature of Internet fax, compared to other Internet communications such as email, is the ability to exchange fax messages with traditional telephone-based fax machines.
A party line is a local loop telephone circuit that is shared by multiple telephone service subscribers.
AT&T Merlin is a corporate telephone system by American Telephone and Telegraph (AT&T) that was introduced in late 1983, when it was branded American Bell Merlin. After the breakup of AT&T in 1984, it was rebranded and later also supplied by Lucent, and Avaya.
A telephone number is a sequence of digits assigned to a fixed-line telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices for data transmission via the public switched telephone network (PSTN) or other public and private networks.
A modem – a portmanteau of "modulator-demodulator" – is a hardware device that converts data from a digital format, intended for communication directly between devices with specialized wiring, into one suitable for a transmission medium such as telephone lines or radio. A modem modulates one or more carrier wave signals to encode digital information for transmission, and demodulates signals to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded reliably to reproduce the original digital data.
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.
Call management is the process of designing and implementing inbound telephone call parameters, which govern the routing of these calls through a network. The process is most prominently utilized by corporations and the call centre industry and has its highest effectiveness when call logging software tools are used. Calls are routed according to the set up of calling features within the given system such as Call queues, IVR menus, Hunt groups and Recorded announcements. Call features provide a customised experience for the caller and maximize the efficiency of inbound call handling. Call management parameters can specify how calls are distributed according to an operator's skill level in relation to a call, the time and/or date of a call, the location of the caller or through automatic routing processes.
A telephone exchange, telephone switch, or central office is a telecommunications system used in the public switched telephone network (PSTN) or in large enterprises. It interconnects telephone subscriber lines or virtual circuits of digital systems to establish telephone calls between subscribers.
