3-Way Call Dial Prefix: routing 3-way calls through a specific trunk (and hearing ringback)

A dial prefix in VICIdial is a short string the system prepends to a number to pick how and where the call routes. The 3-Way Call Dial Prefix setting applies that idea specifically to the third leg an agent dials. It is small, but it controls both which trunk carries the call and whether the agent hears the line ringing.

What the setting does

This defines what is used as the Dial prefix for Three-way call dials. The default is empty, and when it is empty the campaign dial prefix is used instead. So if you do nothing, your 3-way calls route exactly like the rest of your Campaign traffic.

The one value worth memorizing is 88. That is the passthru prefix, and it exists so the agent can hear ringing on the third leg as it connects. Without ringback, an agent on a Three-way call sometimes cannot tell whether the specialist is ringing, busy, or already picked up.

Why ringback matters on a handoff

Picture a Fronter doing a Warm transfer to a Closer. They click to dial the closer and then sit in silence, unsure if anyone is ringing. They either talk over a connect or hang up too early. Setting the prefix to 88 gives them the ringback tone so they know exactly when to start the introduction.

If your audio path normally swallows that ringback, this single setting fixes the no-ringback complaint without touching your dialplan. It is the first thing to check when agents say a 3-way feels dead until the other side speaks.

Routing through a specific trunk

Because the value is a prefix, you can also point 3-way calls at a particular Trunk by using the prefix your dialplan maps to it. That lets the third leg leave on a different Carrier than your normal outbound traffic, useful when one route has better connectivity to the numbers your agents transfer to.

This matters most when your transfers leave the building. If your fronters hand off to an external closer center over one specific Carrier, routing only the 3-way leg through that route keeps call quality consistent without changing how the rest of your Campaign dials. The customer leg and the third leg can travel different paths, and this prefix is the lever for the third one.

Keep in mind that empty is a real, deliberate value, not a blank you forgot to fill in. An empty prefix means inherit the Campaign dial prefix, which is the right default for most floors. Only override it when you specifically want ringback or a dedicated route.

How the prefix decides routing

flowchart TD
  A[Agent dials third leg] --> B{3-Way Dial Prefix}
  B -->|Empty| C[Use campaign dial prefix]
  B -->|88 passthru| D[Route with ringback audible]
  B -->|Custom prefix| E[Route via mapped trunk]
  C --> F[Call leaves the dialer]
  D --> F
  E --> F
  F --> G[Third party rings]
  G --> H[Agent hears ringback if 88]

Setting it

1. Open the campaign detail screen and find the 3-way settings group.
2. Leave the prefix empty to inherit the campaign prefix, or enter 88 for audible ringback.
3. To force a trunk, enter the prefix your dialplan associates with it, then test one call.

The prefix decides the path; a separate setting decides the number the far end sees. Pair this with the right choice in our note on 3-Way Call Outbound CallerID so both the route and the ID line up.

Our transfers and closers guide covers the rest of the 3-way controls. If you would rather have routing and ringback that just work, see our pricing.