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Overview

The sip:refer verb performs a blind transfer of a call by sending a SIP REFER.

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Example

{
  "verb": "sip:refer",
  "referTo": "+15083084809",
  "actionHook": "/action"
}

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Parameters

ParameterTypeRequiredDescription
referTostringYesA SIP URI or a phone number/user identifier.
actionHookstringNoA webhook to call when the transfer has completed.
eventHookstringNoA webhook to call when NOTIFY messages of follow-on call status are received.
headersobjectNoAdditional SIP headers to include in the response.
referredBystringNoA SIP URI or a phone number/user identifier. If not provided, it will default to the identity of the party being transferred.
The sip:refer verb completes when one of these conditions are met:
  • a failure response is received to the REFER
  • a 202 Accepted is received in response to the REFER, and a NOTIFY of the follow-on call status with a final call status is received.
The sip:refer has an action hook that will provide details of the final result, as well as an event hook that is called for every NOTIFY received after a successful REFER.

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actionHook properties

The actionHook webhook will contain the following additional parameters:
  • referStatus: the sip status response to the REFER request
  • final_referred_call_status: the final sip status of the subsequent call to the transferee. This is only provided in the case where the REFER is accepted and NOTIFY requests are received from the far end.

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eventHook properties

The eventHook webhook will contain two parameters: event and call_status. The event parameter will always be transfer-status and the call-status will contain a sip status received in a NOTIFY after a successful REFER; e.g. 
{
  "event": "transfer-status",
  "call_status": "180"
}