Signaling (telecommunications)

signalsignalingout-of-band signalingsignallingcontrol signalsignalsout-of-band signallingout-of-bandcall handling processescommunication systems
In telecommunication, signaling is the use of signals for controlling communications.wikipedia
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In-band signaling

in-bandin-band signallinginband
In the public switched telephone network (PSTN), in-band signaling is the exchange of call control information within the same physical channel, or within the same frequency band, that the telephone call itself is using.
In telecommunications, in-band signaling is the sending of control information within the same band or channel used for data such as voice or video.

Signal

signalselectrical signalsignaling
In telecommunication, signaling is the use of signals for controlling communications.
In telephone networks, signaling, for example common-channel signaling, refers to phone number and other digital control information rather than the actual voice signal.

Telecommunication circuit

circuitcircuitsconnection
This may constitute an information exchange concerning the establishment and control of a telecommunication circuit and the management of the network—in contrast to manual setup of circuits by users or administrators, for example the sending of a signal from the transmitting end of a telecommunication circuit to inform a user at the receiving end that a message is to be sent.

Signalling System No. 7

SS7Signaling System 7Signalling System 7
Out-of-band signaling has been used since Signaling System No. 6 (SS6) was introduced in the 1970s, and also in Signalling System No. 7 (SS7) in 1980 which became the standard for signaling among exchanges ever since.
7 (SS7''') is a set of telephony signaling protocols developed in 1975, which is used to set up and tear down telephone calls in most parts of the world-wide public switched telephone network (PSTN).

Signaling System No. 6

Signalling System No. 6
Out-of-band signaling has been used since Signaling System No. 6 (SS6) was introduced in the 1970s, and also in Signalling System No. 7 (SS7) in 1980 which became the standard for signaling among exchanges ever since.
6 (SS6''') was introduced in the 1970s as an early common channel signalling method for telecommunication trunks between international switching centers (ISCs).

Communication channel

channelchannelscommunications channel
Out-of-band signaling is telecommunication signaling on a dedicated channel separate from that used for the telephone call.
The information is carried through the channel by a signal.

Public switched telephone network

PSTNpublic telephone networktelephone network
In the public switched telephone network (PSTN), in-band signaling is the exchange of call control information within the same physical channel, or within the same frequency band, that the telephone call itself is using.
Bells were soon added to stations for signaling, so an attendant no longer needed to wait for the whistle.

Line signaling

line signallingsupervisionline
Line signaling is concerned with conveying information on the state of the line or channel, such as on-hook, off-hook (answer supervision and disconnect supervision, together referred to as supervision), ringing, and hook flash.
Line signaling is a class of telecommunications signaling protocols.

Blue box

2600 Hza 2600-hertz-soundBlue box (phreaking)
In the middle 20th century, supervision signals on long-distance trunks in North America were primarily inband, for example at 2600 Hz, necessitating a notch filter to prevent interference.
Subsequent telephone switching technologies used out-of-band signaling methods in the form of Common Channel Interoffice Signaling (CCIS) in a separate channel not accessible to the caller.

Rotary dial

rotary telephonedialrotary phone
In the first half of the 20th century, addressing formation is done by using a rotary dial, which rapidly breaks the line current into pulses, with the number of pulses conveying the address.
A rotary dial is a component of a telephone or a telephone switchboard that implements a signaling technology in telecommunications known as pulse dialing.

Pulse dialing

dial pulsepulse diallingpulse dial
In the first half of the 20th century, addressing formation is done by using a rotary dial, which rapidly breaks the line current into pulses, with the number of pulses conveying the address.
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.

Dual-tone multi-frequency signaling

DTMFtouch-tonedual-tone multi-frequency
An example is dual-tone multi-frequency signaling (DTMF), which is used on most telephone lines to customer premises.
Dual-tone multi-frequency signaling (DTMF) is a telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers.

Channel-associated signaling

CASChannel Associated Signalingchannel associated
Channel-associated signaling (CAS) employs a signaling channel which is dedicated to a specific bearer channel.
Channel-associated signaling (CAS), also known as per-trunk signaling (PTS), is a form of digital communication signaling.

Multi-frequency signaling

multi-frequencyMFmultifrequency
Most forms of R2 register signaling are compelled (see R2 signaling), while R1 multi-frequency signaling is not.
In telephony, multi-frequency signaling (MF) is a signaling system that was introduced by the Bell System after World War II.

Common-channel signaling

Common Channel SignalingCommon Channel Interoffice Signalingcommon
Common-channel signaling (CCS) employs a signaling channel which conveys signaling information relating to multiple bearer channels.
In telecommunication, common-channel signaling (CCS), or common-channel interoffice signaling (CCIS), is the transmission of control information (signaling) via a separate channel than that used for the messages, The signaling channel usually controls multiple message channels.

Supervision (telephony)

answer supervisionCalling Party ControlDisconnect supervision
Line signaling is concerned with conveying information on the state of the line or channel, such as on-hook, off-hook (answer supervision and disconnect supervision, together referred to as supervision), ringing, and hook flash.
Some digital trunks, such as SS7, use out-of-band signaling to indicate termination of a call.

E and M signaling

E&M
E and M signaling is a type of supervisory line signaling that uses DC signals on separate leads, called the "E" lead and "M" lead, traditionally used in the telecommunications industry between telephone switches.

Telephone

phonetelephonesLocal Telephone Service
In the early days of telephony, with operator handling calls, the addressing formation is by voice as "Operator, connect me to Mr. Smith please".
Signalling began in an appropriately primitive manner.

2600 hertz

2600Captain Crunch whistle
2600 Hz is a frequency in hertz (cycles per second) that was used by AT&T as a steady signal to mark currently unused long-distance telephone lines.

Metering pulse

In telecommunications, metering pulses are telephone signals sent by telephone exchanges to metering boxes and payphones aimed at informing the latter of the cost of ongoing telephone calls.

Telecommunication

telecommunicationscommunicationstelecom
In telecommunication, signaling is the use of signals for controlling communications.

Communication

communicationsSocial Communicationcommunicate
In telecommunication, signaling is the use of signals for controlling communications.

Telephone line

phone linelinetelephone cable
An example is dual-tone multi-frequency signaling (DTMF), which is used on most telephone lines to customer premises.

Ringing (telephony)

ringingMagenta boxcall bell
Line signaling is concerned with conveying information on the state of the line or channel, such as on-hook, off-hook (answer supervision and disconnect supervision, together referred to as supervision), ringing, and hook flash.