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

QSIG Single-Step Call TransferSingle-Step call transfer is defined in ECMA specifications ECMA 300and ECMA 299. Single-Step call transfer uses a single line.To transfer a call, the Omvia Media Server sends a message to theswitch, which contains a number to which the call can be redirected. Thecall can be transferred in either the Alerting (Ringing) or Connectedstates.The characteristics of QSIG Single-Step call transfer are shown inTable 3-9.Table 3-9. QSIG Single-Step Call Transfer CharacteristicsSpan Type Transfer Type connect UserDLL?E1 Single Line Transfer NoHicom Euro-ISDN Call TransferFor more information onthe Hicom ISDN protocol,refer to “Hicom ISDNProtocol,” Chapter 9.The Siemens Hicom 300E switch employs standard Euro-ISDN that isbased on the ITU-T Q.931 standard. The Hicom uses a custom versionof call transfer that functions very much like Single Step Call Transfer.A message is sent in the D channel, which contains the transferdesignation number. Then, the Omvia Media Server releases the call.The switch transfers the original call to the new number. A standardCallTransfer form is used within InVision to invoke the transfer.The characteristics of Hicom Euro-ISDN call transfer are shown inTable 3-10.Table 3-10. Hicom Euro-ISDN Call Transfer CharacteristicsSpan Type Transfer Type connect UserDLL?E1 Single Line Transfer No3-10 ISDN Protocol Administrator’s and Developer’s Guide 60001262, First Edition