SIP and Call Transfer tags

This section describes the use of the Blueworx Voice Response System Variables SV541, SV542, and SV543 which are used to pass additional signaling information between an application and the SIP stack and the SIP tags that are supported.

As described in Voice over IP tags, there are three Blueworx Voice Response System Variables that are used to pass additional signalling information between an application and the SIP stack. These are:

SV541 - for supported tags that are sent to the SIP network (on outbound calls and transfer requests)
SV542 - for supported tags that are received from the SIP network (on inbound calls)
SV543 - for reviewing of far end hang up reasons

To ensure that these three System Variables contain the correct information, the Call Information Type parameter must be set to Signalling Process in the System Configuration GUI. See Call Information Type for more information.

For an inbound call the following tags are supported:

TO_HDR, FROM_HDR, REQ_HDR, CALLINFO_HDR, CALLID_HDR, DIV_HDR, A_LANG_HDR, PRIVACY_HDR, SUBJECT_HDR
Used in SV542 on an inbound INVITE.
The first ten other (non-standard) headers in the configuration file /usr/lpp/dirTalk/db/sys_dir/voip/siphdrtags.cfg can be used in SV542 on an inbound INVITE.

For an outbound call the following tags are supported:

TO_HDR, FROM_HDR,REQ_HDR, DIV_HDR, A_LANG_HDR, PRIVACY_HDR, PASSID_HDR, RPARTYID_HDR
Used in SV541 on outbound INVITE (MakeCall action).
The first ten other (non-standard) headers in the configuration file /usr/lpp/dirTalk/db/sys_dir/voip/siphdrtags.cfg can be used in SV541 on an outbound INVITE.

For a near-end hangup (TerminateCall action), the following tag used in SV541 is supported:

SUBJECT_HDR

On a blind (REFER) transfer the following tags are supported:

TO_HDR, FROM_HDR

On an attended (REFER/Replaces) transfer the same tags as outbound call are supported:

TO_HDR, FROM_HDR, REQ_HDR, DIV_HDR, A_LANG_HDR, PRIVACY_HDR, PASSID_HDR, RPARTYID_HDR

In addition to the above, there are three tags that are used to control the internal operation of SIP transfer operations:

CONSULT:
Used in SV541 prior to a TransferCall action being issued to set up the consultation leg of an attended transfer.
TRANSFER:
Used in SV541 prior to a TransferCall being issued to actually perform the SIP transfer operation (REFER/REPLACES) for an attended transfer.
XFER_TIMER:
Used in SV541 prior to a outbound REFER (TransferCall action) for blind transfer.

See SIP Header tags and Transfer control tags for details of how to implement Call Transfer under SIP.