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In telecommunication, signaling (signalling in British English) has the following meanings: *the use of signals for controlling communications *the information exchange concerning the establishment and control of a telecommunication circuit and the management of the network, in contrast to user information transfer *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. Signaling systems may be classified based on several principal characteristics. ==In-band and out-of-band signaling== In the public switched telephone network (PSTN), in-band signaling is the exchange of call control information within the same channel that the telephone call itself is using. An example is dual-tone multi-frequency signaling (DTMF), which is used on most telephone lines to customer premises. Out-of-band signaling is telecommunication signaling on a dedicated channel separate from that used for the telephone call. 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.〔(【引用サイトリンク】title=Signaling in/out-of-band Definition )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Signaling (telecommunications)」の詳細全文を読む スポンサード リンク
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