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Types Of Signalling Information And Call Connection Procedure
Call request and Release information Call request information i.e. calling subscriber off hook or seizure signal or an incoming trunk, indicates a new call. On its receipt. the exchange connects an appropriate equipment for receiving address information ( called number). Release information i.e. on hook or release signal on a trunk indicates that the call is over. The exchange releases all the equipment held out for the call, and clears up any other information used for setting up at including the call. Selection ( Address) information. When the exchange is ready to receive the address information. It sends back a request which is known as proceed to send (PTS) signal in trunk signaling and dial tone in subscriber signalling. Address information essentially comprises of full or part of the subscribers number and possibly additional service data. End of selection information This information indicates the status of the called line, or the reason for non completion of the call attempt, essentially indicating called line free or busy. Supervisory information It specifies the on/off hook condition of a subscriber after the connection has been setup i. subscriber off hook subscriber has answered and charging may commence. ii. subs on hook:- subscriber has hung up to terminate the call, and the call is disconnected after a time delay if the subscriber does not hang up. The on/off-hook conditions of the subscriber are covered by call request and release information. Call connection The interchange of signaling information can be illustrated with the help of a typical call connection sequence. The circled number in correspond to the steps listed below i. A request for originating a call is initiated when the subscriber lifts the handset. ii. The exchange sends dial-tone to the subscriber to indicate to him to start dialing. iii. The called number is transmitted to the exchange, when the calling subscriber dials the number. iv. if the number is free, the exchange sends ringing current to him. v. Feed-back is provided to the calling subscriber by the exchange by sending. a. Ring-back tone, if the calld subs is free b. Busy tone if the subscriber is busy or c. Recorded message, if provision exists, for non completion of call due to some other constraint vi. The call subs indicates acceptance of the incoming call by lifting the handset Article Directory: http://www.articledashboard.com Irfan Mansuri Start a Latest Results Forum Bank Jobs Forum |
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