Early access: these interfaces are documented as drafts. Confirm commands, packages and endpoints with us before use.

Blind transfers, availability checks and hold music

Transfer calls from voice agents to people, directly or with an availability check. Return to the agent if nobody answers, with configurable hold music.

TrunkBeam supports two ways to transfer a call from a voice agent to a person. Both modes and configurable hold music are already available. Platform access is arranged through early access.

Blind transfer: hand the call over directly

A blind transfer hands the call directly to the configured destination. The agent does not wait for an answer and leaves the conversation. This flow does not include a return to the agent.

It suits destinations that manage the next step themselves, such as a phone system with its own queue. A successful handover does not necessarily mean that a person has answered.

Transfer with an availability check

Use an availability check when you want the agent to resume the call if nobody answers:

  1. The agent announces the transfer.
  2. The destination rings while the caller hears your configured hold music.
  3. If someone answers, the caller is connected and the agent leaves the call.
  4. If the destination is busy or nobody answers, the conversation with the agent resumes.

The agent can say, for example: “No one is available at reception right now. How else can I help you?” Your conversation logic determines whether to take a callback request or help the caller directly.

An availability check does not promise a separate consultation between the agent and the employee. That consultative flow is often called a “warm transfer” or “attended transfer”. The flow described here checks whether the destination answers and returns the caller to the agent when needed.

Configure your hold music

Different hold music is available for the waiting phase. You configure what callers hear while the destination’s availability is being checked. The waiting phase ends when the destination answers or the caller returns to the agent.

This applies to the actual call flow. The example on the homepage illustrates the behavior without placing calls or saving settings.

SIP REFER and your voice stack

SIP REFER can initiate a transfer within a SIP network. Your voice stack must support the required signaling. Direct handover and return-to-agent behavior also depend on the integration and the selected flow.

The commands and interfaces in this documentation are drafts. We agree the exact setup for your stack during onboarding. We do not claim that every listed platform supports every transfer mode.

Technical background: IETF RFC 5589 on SIP Call Transfer.

Destinations and call costs

Define which destinations your agent is allowed to use. Agree target numbers, SIP addresses and unavailable-destination handling before your first production call.

A transfer may create a connection to the destination in addition to the inbound connection. You receive the applicable rates and billing rules before you start. See pricing and billing.

Access and next steps

Connecting an existing voice agent? Request early access or read about SIP connectivity.

Connect your stack to TrunkBeam