Call Clearing courtesy of google
6 Call Clearing- 6.1 Terminal Initiated Clearing
6.1.1 By A Calling Terminal
The DDI will detect a calling terminal returning to an †˜On-Hookââ‚ ¬Ã¢â€žÂ¢ state and initiate a †œNetwork Initiated Clearingââ‚ ‚¬Ã‚ sequence (described in 6.2 below) with the additional of an information message being sent to the called customer indicating the †˜CallerÃƒÂ¢à ¢â€šÂ¬Ã¢â€Š¾Ã‚¢ has cleared.
6.1.2 By A Called Terminal
When the called terminal returns to the †˜On-Hookââ‚ ¬Ã¢â€žÂ¢ state the DDI will detect the change of condition and initiate a time-out process lasting up to two minutes. After the time-out period has expired a †œNetwork Initiated Clearingââ‚ ‚¬Ã‚ sequence (described in 6.2 below) is offered to the calling terminal
- 6.2 Network Initiated Clearing
The DDI interface will offer a sequence of clearing signals at the NTP as a result of terminal sending the call or a failure to send valid routing digits during call set-up
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