Simultaneous dialing - Vobiz

Add sibling <Number> elements to one <Dial> when you want Vobiz to attempt several PSTN destinations concurrently. Vobiz bridges the first destination that answers and cancels the remaining B-legs.

Example

<?xml version="1.0" encoding="UTF-8"?>
<Response>
  <Dial
      callerId="+14155550100"
      callerName="Vobiz Transfer"
      timeout="30"
      callbackUrl="https://example.com/dial-events"
      callbackMethod="POST"
      action="https://example.com/dial-result"
      method="POST"
      redirect="false">
    <Number>+14155550101</Number>
    <Number>+14155550102</Number>
  </Dial>
  <Hangup/>
</Response>

Replace callerId with a Vobiz number owned or authorized by your account. The receiving carrier and device decide whether to display callerName.

How the race is reported

DialBLegPosition follows the child order:

Child	Position
First `<Number>`	`1`
Second `<Number>`	`2`

The winning destination receives the normal answer, connected, and hangup lifecycle. When another destination loses the race, its DialHangup callback reports:

Event=DialHangup
DialAction=hangup
DialBLegHangupCause=LOSE_RACE
DialBLegHangupCauseCode=9000
DialBLegHangupCauseName=Lost Race
DialBLegHangupSource=Vobiz

Treat LOSE_RACE as an expected simultaneous-dial outcome, not as a destination or carrier failure.

Application handling

Match callbacks to a destination using DialBLegUUID, DialBLegTo, and DialBLegPosition.
Do not retry a LOSE_RACE leg as an error while another destination is connected.
Use the final action request for the overall Dial result.
Set timeout explicitly to control how long unanswered destinations remain in the race.

Next steps