Editing Signaling (telecommunications) (section)

===Line versus register signaling===
[[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 (telephony)|supervision]]''), [[Ringing (telephony)|ringing]], and [[hook flash]].  
[[Register signaling]] is concerned with conveying addressing information, such as the calling and/or called [[telephone number]]. In the early days of [[telephony]], with [[Switchboard operator|operator]] handling calls, the addressing formation is by voice as "Operator, connect me to Mr. Smith please". In the first half of the 20th century, addressing formation is done by using a [[rotary dial]], which rapidly breaks the line current into [[Pulse dialing|pulses]], with the number of pulses conveying the address. Finally, starting in the second half of the century, address signaling is by [[DTMF]].