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204 TELEPHONE USER PARTFigure 9.2-1. Initial Address message. (From Rec. Q.723. Courtesy of ITU-T.)Message Indicators (A,…,K). A set of indicators is used by the exchanges alongthe connection during the call setup:(BA)Nature of (Called) Address Indicator00 Subscriber number10 National number (area code þ subscriber number)11 International number (country code þ nationalnumber)(DC)Nature of Circuit Indicator00 No satellite circuit in connection01 One satellite circuit in connection(FE)Continuity Check Indicator00 Continuity check not required01 Continuity check required on this circuit10 Check not required on this circuit but has beenperformed on a previous circuit(G)Echo Control Indicator0 Outgoing suppressor/canceler not included1 Outgoing suppressor/canceler included(H)Incoming Call Indicator0 Not an incoming international call1 Incoming international call