A.originationmessage→BSACK→TCHpreamble→Channelassignmentmessage→BSACK→MSACK→ServiceConnectmessage→Serviceconnectcompletion→assignmentcomplete
B.originationmessage→BSACK→ServiceConnectmessage→TCHpreamble→BSACK→MSACK→Channelassignmentmessage→Serviceconnectcompletion→assignmentcomplete
C.originationmessage→BSACK→Channelassignmentmessage→TCHpreamble→BSACK→MSACK→ServiceConnectmessage→Serviceconnectcompletion→assignmentcomplete
D.OriginationMessage→CMServiceRequest→TchPreamble→Establish→AssignmentComplete→Allocation；