Call transfer

Most voice response services offer the caller the opportunity to transfer a call. Call transfer can be provided in several ways, although the only standard method uses PABX station or Centrex line features. Other methods of transfer include a release link trunk, unique T1 or E1 protocols, or exchange data link.

There are two types of call transfer:

Screened transfer is usually preferable, but a blind transfer does reduce the duration of a successful transfer process and may be acceptable.

Screened transfer

With a screened transfer, the state table places the caller on hold (suspending the call) and completes the transfer only if the call to the third party is answered. If the state table detects busy tone while transferring a call, or if the third party does not answer, the state table can take one of the following actions:

Blind transfer

With a blind transfer, the state table places the caller on hold, sends the address of the third party, and then disconnects from the call. If the transfer is unsuccessful, the switch usually places a new call to the party that originally initiated the transfer request.

Implementing call transfer with Blueworx Voice Response

With channel associated signaling (CAS), Blueworx Voice Response can generate call transfer request signals using feature codes (character strings consisting of 0 through 9, *, and #) with or without hook or ground flash. To transfer a call, invoke the TransferCall action. With the Transfer Call Request Signal parameter (in the Signaling Type parameter group) set to Feature Code, the Transfer Call Feature Code (in the same group) identifies the character string recognized by the switch as a call transfer request.

If the CAS protocol being used does not support call transfer, but the switch has a host access control link that does support it, a custom-written signaling process (see the Blueworx Voice Response for AIX: Programming for the Signaling Interface information for details).