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- Single-frequency_signaling abstract "Single-frequency signaling (SF) is line signaling (in telephony) in which dial pulses or supervisory signals are conveyed by a single voice-frequency tone in each direction. SF and similar systems were used in 20th-century carrier systems.An SF signaling unit converts DC signaling (usually, at least in long distance circuits, E&M signaling) to a format (characterized by the presence or absence of a single voice-frequency tone), which is suitable for transmission over an AC path, e.g., a carrier system. The SF tone is present in the on-hook or idle state and absent during the seized state. In the seized state, dial pulses are conveyed by bursts of SF tone, corresponding to the interruptions in dc continuity created by a rotary dial or other DC dialing mechanism. The SF tone may occupy a small portion of the user data channel spectrum, e.g., 1600 Hz or 2600 Hz (SF "in-band signaling)". There may be a notch filter at the precise SF frequency, either filtering the circuit at all times or only when the circuit is off-hook, to prevent the user from inadvertently disconnecting a call if the users voice has a sufficiently strong spectral content at the SF frequency, a falsing condition known as talk-off. Notoriously, this property was exploited by blue boxers and other toll fraudsters. The SF tone may also be just outside the user voice band, e.g., 3600 Hz. The Defense Data Network (DDN) transmitted DC line signaling pulses or supervisory signals, or both, over carrier channels or cable pairs on a four wire circuit basis using a 2600 Hz signal tone. The conversion into tones, or vice versa, is done by SF signal units.SF was developed in the early 20th century and standardized in middle century. It declined in the 1970s due to the adoption of T-carrier, and was largely abandoned late in the century in favor of common-channel signaling.".
- Single-frequency_signaling wikiPageID "41715".
- Single-frequency_signaling wikiPageLength "2577".
- Single-frequency_signaling wikiPageOutDegree "35".
- Single-frequency_signaling wikiPageRevisionID "683418593".
- Single-frequency_signaling wikiPageWikiLink 2600_Hz.
- Single-frequency_signaling wikiPageWikiLink Alternating_current.
- Single-frequency_signaling wikiPageWikiLink Band-stop_filter.
- Single-frequency_signaling wikiPageWikiLink Blue_box.
- Single-frequency_signaling wikiPageWikiLink Cable.
- Single-frequency_signaling wikiPageWikiLink Carrier_signal.
- Single-frequency_signaling wikiPageWikiLink Carrier_system.
- Single-frequency_signaling wikiPageWikiLink Carrier_wave.
- Single-frequency_signaling wikiPageWikiLink Category:Telephony_signals.
- Single-frequency_signaling wikiPageWikiLink Channel_(communications).
- Single-frequency_signaling wikiPageWikiLink Common-channel_signaling.
- Single-frequency_signaling wikiPageWikiLink Data.
- Single-frequency_signaling wikiPageWikiLink Defense_Data_Network.
- Single-frequency_signaling wikiPageWikiLink Dial_pulse.
- Single-frequency_signaling wikiPageWikiLink Dialing.
- Single-frequency_signaling wikiPageWikiLink Dialling.
- Single-frequency_signaling wikiPageWikiLink Direct_current.
- Single-frequency_signaling wikiPageWikiLink E_and_M_signaling.
- Single-frequency_signaling wikiPageWikiLink Falsing.
- Single-frequency_signaling wikiPageWikiLink Four-wire_circuit.
- Single-frequency_signaling wikiPageWikiLink Four_wire_circuit.
- Single-frequency_signaling wikiPageWikiLink Frequency.
- Single-frequency_signaling wikiPageWikiLink In-band_signaling.
- Single-frequency_signaling wikiPageWikiLink Line_signaling.
- Single-frequency_signaling wikiPageWikiLink Long-distance_calling.
- Single-frequency_signaling wikiPageWikiLink Long_distance_calling.
- Single-frequency_signaling wikiPageWikiLink Notch_filter.
- Single-frequency_signaling wikiPageWikiLink Off-hook.
- Single-frequency_signaling wikiPageWikiLink On-hook.
- Single-frequency_signaling wikiPageWikiLink Pulse_dialing.
- Single-frequency_signaling wikiPageWikiLink Rotary_dial.
- Single-frequency_signaling wikiPageWikiLink Signaling_(telecommunications).
- Single-frequency_signaling wikiPageWikiLink Signalling_(telecommunication).
- Single-frequency_signaling wikiPageWikiLink T-carrier.
- Single-frequency_signaling wikiPageWikiLink Telephone_call.
- Single-frequency_signaling wikiPageWikiLink Telephony.
- Single-frequency_signaling wikiPageWikiLink Transmission_(telecommunications).
- Single-frequency_signaling wikiPageWikiLink User_(telecommunications).
- Single-frequency_signaling wikiPageWikiLink Voice-frequency.
- Single-frequency_signaling wikiPageWikiLink Voice_frequency.
- Single-frequency_signaling wikiPageWikiLinkText "Single-frequency signaling".
- Single-frequency_signaling wikiPageWikiLinkText "single frequency tones".
- Single-frequency_signaling wikiPageWikiLinkText "single frequency".
- Single-frequency_signaling wikiPageWikiLinkText "single-frequency signaling".
- Single-frequency_signaling hasPhotoCollection Single-frequency_signaling.
- Single-frequency_signaling wikiPageUsesTemplate Template:FS1037C_MS188.
- Single-frequency_signaling wikiPageUsesTemplate Template:Reflist.
- Single-frequency_signaling wikiPageUsesTemplate Template:Telecommunications.
- Single-frequency_signaling subject Category:Telephony_signals.
- Single-frequency_signaling hypernym Line.
- Single-frequency_signaling type Article.
- Single-frequency_signaling type Article.
- Single-frequency_signaling type Source.
- Single-frequency_signaling comment "Single-frequency signaling (SF) is line signaling (in telephony) in which dial pulses or supervisory signals are conveyed by a single voice-frequency tone in each direction.".
- Single-frequency_signaling label "Single-frequency signaling".
- Single-frequency_signaling sameAs m.0bgf2.
- Single-frequency_signaling sameAs Q7523724.
- Single-frequency_signaling sameAs Q7523724.
- Single-frequency_signaling wasDerivedFrom Single-frequency_signaling?oldid=683418593.
- Single-frequency_signaling isPrimaryTopicOf Single-frequency_signaling.