ISDN Protocol Administrator's and Developer's Guide ... - Intervoice

Defining the SubroutinesQSIG Single Step TransferSingle Step Transfer is defined in the ECMA specifications ECMA 299and ECMA 300. It uses a single line.In single step mode, a message is sent to the switch that contains thenumber to which the call is redirected. The call can be transferred in twoways:• Alerting (Called party Ringing)• ConnectedThe Single Step Transfer is an efficient transfer that does not require anadditional outbound line. It also does not require an outbound call to beplaced before the transfer can occur. The Single Step Transfer requiresonly one toolkit call to accomplish the task of transferring the inboundcaller to any number allowed by the transferring switch.In a QSIG Single Step Transfer, the Omvia Media Server receives aninbound call and answers it. When the caller requests a transfer, theapplication uses a toolkit call to send a Facility message to the switch.For more information onASN.1, see Series X:Data Networks and OpenSystem Communications– OSI networking andsystem aspects –Abstract Syntax NotationOne (ASN.1).The Facility message uses a Single Step Transfer Invoke (part of theROSE component of ASN.1) and the telephone number of the switch totransfer the inbound caller. The switch either completes the transfer,releasing the inbound line to the Omvia Media Server, or it respondswith a Facility message containing an error code.60001262, First Edition QSIG Protocol 5-17