Transfer to number: hand a call to a person

Transfer to number lets the agent move a phone call to a person: a phone number, or a SIP URI on your phone system. You write the conditions, in plain language, and the agent picks the rule that fits during the call. It works on phone calls only. A website call or a text conversation has no phone line to move. There are two places to set it up:

• Tools, for transfers the agent may make at any point in the call. This is the system tool, and it needs no workflow.
• A Transfer step in the agent’s workflow, for a transfer at a fixed point in the flow, such as after a lead signs.

Both use the same fields and the same three transfer types.

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Turn it on

1. Open Tools in the agent sidebar.
2. Under System tools, click the switch beside Transfer to number. The Edit system tool panel opens.
3. Choose Add rule and fill in the rule. Add one rule per destination.
4. Choose Save. The tool turns on when it saves. Cancel leaves it off.

The settings save to the branch’s draft. Publish before live calls use them. Description tells the agent how and when to transfer. Leave it blank to use the default, which tells the agent to help first, transfer when the caller asks for a person or needs something it can’t do, and write a short summary for the person who answers. Show default puts that text in the field so you can edit it.

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Rule fields

Write conditions so that no two overlap, because the agent picks one rule:

The caller asks to speak to someone about an invoice or a refund.

Type {{ in a condition to add a variable.

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Transfer types

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Conference

The default. The agent tells the caller it’s putting them through, and the caller hears hold music while Centillion calls the destination from your line. When someone answers, they first hear the agent’s summary of the call on their own, then join the caller. The caller doesn’t hear the summary. The agent then leaves the call. The agent writes the summary when it transfers: who is calling, what they need and what it already did. On a realtime voice the summary is read in a standard voice, because the realtime model has no separate voice to read it. A workspace with regulated data gets no summary on a realtime voice; the person is connected straight away.

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Blind

Centillion calls the destination and the caller hears it ring. The person sees the caller’s own number, the way a forwarded call shows it. If your carrier doesn’t let your line show another number, the call goes out from your line’s number instead. When someone answers, the agent leaves the call. There is no summary.

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SIP REFER

Your carrier moves the call. The caller’s call leaves Centillion and rings the destination directly. Use it for a SIP URI, for custom headers or UUI, and for a contact center that expects calls this way. Your SIP trunk must allow transfers by SIP REFER. On a Twilio Elastic SIP Trunk, that’s the trunk’s Call Transfer (SIP REFER) setting.

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Destinations from a variable

Choose Phone Number as Dynamic Variable or SIP URI as Dynamic Variable when a business system decides who answers. Enter the variable’s name, for example jake_transfer_uri. A tool can fill it from its response, or the conversation can set it with Update state. The agent reads the variable when the transfer starts. If it’s missing, invalid or a sensitive variable, the caller stays with the agent.

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Post-dial digits

Post-dial digits dial an extension or answer a phone menu once the person’s line picks up. Turn on Post-dial digits, then choose:

• Constant value, and type the digits.
• Dynamic variable, and enter the name of a variable that holds them.

Use 0-9, * and #. w waits half a second and W waits one second, so ww1234 waits one second and dials extension 1234.

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Custom headers and UUI

With SIP REFER, Custom Headers adds X- headers to the transfer, such as X-Lead-Id. A header’s value can be fixed or a variable: type {{ in the value to choose one. User-to-User Information (UUI) carries a short payload to the receiving phone system in the Refer-To header. Enter it as plain text, with {{variables}} if you need them. Centillion sends it hex-encoded. Some systems need a Protocol discriminator, a hex octet such as 04, either before the payload or as a header parameter. Check what your receiving system expects. Sensitive variables can’t be sent in headers or UUI.

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In a workflow

Add a Phone number transfer step from the node menu. On the canvas it reads Transfer, with its destination underneath: the number, the SIP URI or the variable it reads. Connect a step to it with a condition, for example “The caller asks for a person”, or an expression that checks a variable, such as a SIP URI a tool returned. When the condition is an LLM condition, the agent writes the summary for a Conference transfer as it moves the call. A workflow’s Transfer steps also appear in the Transfer to number panel under Workflow transfers. Select the ones the system tool may use.

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Which lines can transfer where

• A number bought through Centillion transfers only to phone numbers in its own country that aren’t premium-rate. It can’t transfer to SIP URIs.
• A number from your own Twilio account or SIP trunk can transfer to any number its carrier allows, and to SIP URIs with SIP REFER.
• Conference and Blind transfers dial out on your line, so the line needs outbound calling. A line without it, or one whose trunk refuses the call before it rings, transfers by SIP REFER instead.

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After the transfer

Once the person answers a Conference or Blind transfer, the agent stops listening and speaking. The caller and the person stay on the line until one of them hangs up, which ends the call for both. The conversation is saved as handed off, and its transcript and recording stop where the agent left. If nobody answers within 30 seconds, or the person’s line is busy or they decline, the caller stays with the agent. It tells them it couldn’t put them through and asks how else it can help.

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Edit as JSON

Edit as JSON shows the tool’s configuration. Each rule has these fields:

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Try it

Call the agent’s phone number and ask for what one of your conditions describes. In Preview the agent picks the rule, but a browser call has no phone line to move, so it tells you it can’t put you through.