A telephone call is a connection over a telephone network between the calling party and the called party. A lot of solicitors use this to call your house at all hours of the day. The public switched telephone network (PSTN) is the concatenation of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the concatenation of the worlds public IP-based packet-switched networks. ... The person who (or device that) initiates a telephone call over the public switched telephone network is the calling party. ... The person who (or device that) answers a telephone is the called party. ...

Information transmission

A telephone call may consist of an ordinary voice transmission using a telephone, a data transmission when the calling party and called party are using modems, or a facsimile transmission when the two parties are using fax machines. Where a telephone call has more than one called party it is referred to as a conference call. The telephone is a telecommunications device which is used to transmit and receive sound (most commonly voice and speech) across distance. ... The human voice consists of sound made by a human using the vocal folds for talking, singing, laughing, screaming. ... The telephone is a telecommunications device which is used to transmit and receive sound (most commonly voice and speech) across distance. ... Data transmission is the conveyance of any kind of information from one space to another. ... A modem (from modulate and demodulate) is a device that modulates an analogue carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... This page is a candidate to be moved to Wiktionary. ... A Samsung fax machine. ... The person who (or device that) answers a telephone is the called party. ... A conference call is a telephone call in which the calling party wishes to have more than one called party listen in to the audio portion of the call. ...

Calls are usually placed through a network (such as the Public Switched Telephone Network) provided by a commercial telephone company. If the caller's wireline phone is directly connected to the calling party, when the caller takes their telephone off-hook, the calling party's phone will ring. This is called a hot line or ringdown. Otherwise, the calling party is usually given a tone to indicate they should begin dialing the desired number. In some (now very rare) cases, the calling party cannot dial calls directly, and is connected to an operator who places the call for them. It has been suggested that Office classification be merged into this article or section. ... A telephone company (or telco) provides telecommunications services such as telephony and data communications. ... In telephony, the term off-hook has the following meanings: The condition that exists when a telephone or other user instrument is in use, , during dialing or communicating. ... In telecommunication, a hotline (also called an automatic signaling service or off-hook service) is a point-to-point communications link in which a call is automatically originated to the preselected destination without any additional action by the user when the end instrument goes off-hook. ... Ringdown: In telephony, 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. ... A telephone operator at work on a private switchboard A telephone operator is either a person who provides assistance to a telephone caller, usually in the placing of operator assisted telephone calls such as calls from a pay phone, collect calls (called reversed-charge calls in the UK), calls which...

Most telephone calls in the world are set up using ISUP messages or one of its variants between telephone exchanges to establish the end to end connection. The ISDN User Part or ISUP is part of the Signaling System #7 which is used to set up telephone calls in Public Switched Telecom Networks. ... A Verizon Central Office in Lakeland, Florida at night. ...

Costs

Some types of calls are not charged, such as local calls dialed directly by a telephone subscriber in Canada, the United States, Hong Kong, or New Zealand (Residential subscribers only). In most other areas, all telephone calls are charged a fee for the connection. Fees depend on the provider of the service, the type of service being used (a call placed from a landline or wired telephone will have one rate, and a call placed from a mobile telephone will have a different rate) and the distance between the calling and the called parties. In most circumstances, the calling party pays this fee. However, in some circumstances such as a reverse charge or collect call, the called party pays the cost of the call. In some circumstances, the caller pays a flat rate charge for the telephone connection and does not pay any additional charge for all calls made. Telecommunication liberalization has been established in several countries to allows customers to keep their local phone provider and use an alternate provider for a certain call in order to save money. In telephony, the term local call has the following meanings: Any call using a single switching facility; that is, not traveling to another telephone network; A telephone call made within a local calling area as defined by the Local exchange carrier; Any call for which an additional charge, , toll charge... A landline or main line is a telephone line which travels through a solid medium, either metal wire or optical fibre. ... Cellular redirects here. ... A collect call (or calling collect, in the UK and other countries, reverse charge call) is a telephone call in which the calling party wants to place a call at the called partys expense. ... A collect call in the USA or reverse charge in the UK and other countries (or calling collect) is a telephone call in which the calling party wants to place a call at the called partys expense. ... Categories: Wikipedia cleanup | Stub ...

Tones

A typical phone call is placed by picking the phone handset up off the base and holding the handset so that the hearing end is next to the users ear and the speaking end is within range of the mouth. Headsets are becoming more and more common, especially in car headsets, thus changing the way that people are conducting telephone calls in modern times. Preceding, during, and after a telephone call is placed, certain tones signify the progress and status of the telephone call: Call progress tones are audible tones sent from the PSTN or a PBX to calling parties to indicate the status of calls. ...

• a dial tone signifying that the call is ready to be placed
• either:
  • a ringing tone signifying that the calling party has yet to answer the telephone
  • a busy signal (or engaged tone) signifying that the calling party's telephone is being used in a telephone call to another person (or is "off the hook" though no number has been dialled, ie the customer does not want to be disturbed)
  • a busy signal (or overflow busy tone) signifying that there is congestion in the telephone network, or possibly that the calling subscriber has delayed too long in dialling all the necessary digits
• status tones such as STD notification tones (to inform the caller that the telephone call is being trunk dialled at a greater cost to the calling party), minute minder beeps (to inform the caller of the relative duration of the telephone call on calls that are charged on a time basis), and others
• a tone (sometimes the busy signal) to signify that the called party has hung up.
• tones used by earlier inband telephone switching systems were simulated by a Black box or a Blue box used by "phone phreaks" to illegally make or receive free trunk/toll calls, see Blue box.

A dial tone is a telephony signal used to indicate that the telephone exchange is working and ready to accept a call. ... A ringback tone (RBT), or audible ringing tone or ringback signal, is the audible ringing that is heard on the telephone line by the calling party after dialing and prior to the call being answered at the distant end. ... A busy signal (or engaged tone) in telephony is an audible or visual signal to the calling party that indicates failure to complete the requested connection of that particular telephone call. ... A busy signal (or engaged tone) in telephony is an audible or visual signal to the calling party that indicates failure to complete the requested connection of that particular telephone call. ... Subscriber trunk dialling (STD) (also known as subscriber toll dialling) is a term for the UK telephone system allowing subscribers to dial trunk calls without operator assistance. ... The blue box previously owned by Steve Wozniak, on display at the Computer History Museum. ...

Patents

• Rabinow, J., U.S. Patent 2813154  -- "Telephone call indicator" -- November 12, 1957