ringdown

Information about ringdown

Not to be confused with Quik Call I.
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. Ringdown (a) is used in manual operation, as distinguished from dialing, (b) uses a continuous or pulsed ac signal transmitted over the line, and (c) may be used with or without a switchboard. The term ringdown originated in magneto telephone signaling in which cranking the magneto in a telephone set would not only ring its bell but also cause a drop to fall down at the central office switchboard, marked with the number of the line to which the magneto telephone instrument was connected. The last ringdown telephone exchange in the United States was located at Bryant Pond, Maine, had 400+ subscribers, and converted to dial service in October 1983.

Source: from Federal Standard 1037C and from MIL-STD-188

Non-operator use

In an application not involving a telephone operator, a two-point automatic ringdown circuit, or ringdown, has a telephone at each end. When the telephone at one end goes off-hook, the phone at the other end instantly rings. There is no dialing and phones without dials are sometimes used.

Many ringdown circuits work in both directions. In some cases a circuit is designed to work in one direction only. That is, going off-hook at one end (end A) rings the other (end B). Going off-hook at end B has no effect at end A.

In some circumstances, the electronics that operate ringing are part of a key service unit. This is the electronics box that operates a multi-line key telephone system. In the wire spring relay vintage Bell System 1A2 key service units, a model 216 automatic ringdown was used to operate the circuit. In the 400-series units, there are a number of different KTUs that operate (supervise) a ringdown including a 415. In other situations, the ringdown is powered and operated by equipment inside the central office.

In the case of enterprises with a PBX switch, the ringdown can be operated by the PBX switch. The switch is programmed to ring a specific extension (the called phone) when a defined extension (the calling phone) goes off-hook. The PBX does not offer dialtone to the calling extension: it only looks for on-hook or off-hook status.

These circuits are used:
  • over high-volume routes where one site calls another very frequently.
Example: an information desk and the information desk staff supervisor's desk.
  • where a tamper-proof ability to call from one point to another is needed.
Example: a phone used to summon a taxicab to an airport or hotel.
  • where the public, or users that are not trained in using a specific office telephone system, must place calls.
Example: the after-hours phone to reach the watchman from the front door at a warehouse.
  • in locations where emergencies are handled and the time required to dial digits would cause an unacceptable delay in handling of an emergency.
Example: an airport control tower to the airport's fire station or fire dispatch center.
  • in situations where the called party needs to be certain of who is calling.
Example: a hospital emergency department and an ambulance dispatch center.

In some cases, automatic ringdown circuits have one-to-many configurations. When one phone goes off-hook, a group of phones is made to ring simultaneously.

In cases where one or both ends of the circuit terminate in a key telephone system, a well-designed system will have no hold feature on the ringdown circuit unless supervision provides a Calling Party Control (CPC) signal.

See also

Quik-Call I, also known as 2+2, is a selective calling method originally used in one-way paging receivers. In US fire service use, the tones are sometimes referred to as ringdown tones.[1] The Quik-Call name is a trademark of Motorola.
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In telecommunication, telephony (IPA pronunciation: [tə'lɛfəˌni]) encompasses the general use of equipment to provide voice communication over distances, specifically by connecting telephones to each other.
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In telecommunication, signalling (UK spelling) or signaling (US spelling) has the following meanings:
  • The use of signals for controlling communications.

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The telephone is a telecommunications device which is used to transmit and receive sound (most commonly speech). Most telephones operate through transmission of electric signals over a complex telephone network which allows almost any phone user to communicate with almost anyone.
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worldwide view.
For the Electric Light Orchestra song, see .
A telephone line or telephone circuit (or just line or circuit within the industry) is a single-user circuit on a telephone communications system.
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relay is an electrical switch that opens and closes under the control of another electrical circuit. In the original form, the switch is operated by an electromagnet to open or close one or many sets of contacts. It was invented by Joseph Henry in 1835.
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Dial may mean:
  • Dial (of telephone), a device for the input of numbers in telephones and similar devices
  • A 'sundial' and/or 'clock dial'
  • Dial, a person's face; slang; v., e.g., P.G.

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In telecommunication, signalling (UK spelling) or signaling (US spelling) has the following meanings:
  • The use of signals for controlling communications.

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A switchboard (also called a manual exchange) was a device used to connect a group of telephones manually to one another or to an outside connection, within and between telephone exchanges or private branch exchanges (PBXs). The user was typically known as an operator.
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worldwide view of the subject.
Please [ improve this article] or discuss the issue on the talk page.
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls.
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Woodstock, Maine

Seal
Motto:
Coordinates:
Country United States
State Maine
County Oxford
Area
 - Town  46.8 sq mi (121.
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Federal Standard 1037C, entitled Telecommunications: Glossary of Telecommunication Terms is a United States Federal Standard, issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, as amended.
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MIL-STD-188 is a series of U.S. military standards relating to telecommunications.

Purpose

Faced with “past technical deficiencies in telecommunications systems and equipment and software…that were traced to basic inadequacies in the application of
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A key system or key telephone system is a multiline telephone system typically used in small office environments.

Key systems are noted for their expandability and having individual line selection buttons for each connected phone line, however some features of a
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A wire spring relay is a type of relay, primarily manufactured by the Western Electric Company for use by the Bell System in electromechanical telephone exchanges. It was licenced for use around the world, and was commonplace in Japan.
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The Bell System was a trademark and service mark used by the United States telecommunications company American Telephone & Telegraph Company (AT&T) and its affiliated companies to co-brand their extensive circuit-switched telephone network and their affiliations with each other.
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worldwide view of the subject.
Please [ improve this article] or discuss the issue on the talk page.
In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls.
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Private Branch eXchange (PBX) is a telephone exchange that serves a particular business or office, as opposed to one that a common carrier or telephone company operates for many businesses or for the general public.
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In telephony, the term off-hook has the following meanings:
  1. The condition that exists when a telephone or other user instrument is in use, i.e., during dialing or communicating.

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courtesy telephones scattered about the premises, usually with a white case or other distinctive color. Most have no dial but rather are simple ringdown stations to reach an operator.
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In computer networks and telecommunications, a dedicated line is a communications cable dedicated to a specific application, in contrast with a shared resource such as the telephone network or the Internet.
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