What the Exten Context field means on a phone

Exten Context is the dialplan context a phone primarily operates in. When the VICIdial client applications dial numbers for this phone, they assume those numbers live in this context. Because of that assumption, the field should point at the widest, most permissive context you have, so the calls the dialer makes on the agent's behalf actually find a route. The default works for most installs and you rarely need to touch it.

What a context does here

A context is a named block of routing rules inside the Dialplan that Asterisk runs. Exten Context names the block the client applications expect to use for this phone. Every number the dialer sends out for the agent is assumed to live in this context, so if it is too narrow, some of those numbers will not route. That is why the guidance is to make it as wide as possible.

It is a per-phone field, set on the same entry as the Extension and the other phone settings. Each device can in theory use a different operating context, though in practice they nearly all share the same wide one.

Why width matters

flowchart TD
  A[Client app dials a number] --> B[Assumes Exten Context]
  B --> C{Context wide enough?}
  C -->|Yes| D[Number routes correctly]
  C -->|No| E[No matching rule]
  E --> F[Call fails to route]

The diagram shows the trap. The client app does not pick a context per number; it uses the one Exten Context names for the whole phone. If that context is missing rules for some of the numbers the dialer tries, those calls fail. A wide context that covers everything the agent might dial keeps things working.

Exten Context versus Phone Context

These two fields are right next to each other and constantly swapped in people's heads. Exten Context is the context the phone primarily operates in, the one the client apps assume for dialing. Phone Context is narrower in purpose: it is the context the phone uses to dial out on its own. Different jobs, different fields.

• Exten Context: the wide context the phone mainly works inside. Keep it broad.
• Phone Context: how the phone dials out by itself. Default is default.

A handy way to remember it: Phone Context is the lock you use to stop a handset dialing out, while Exten Context is the broad lane the dialer drives in. You do not narrow Exten Context to restrict agents; you change Phone Context for that.

When to change it

For a standard outbound or inbound setup, leave Exten Context at its default. You only adjust it if your server uses a custom context for the numbers agents dial, and even then you want the broadest one that covers every route. Setting it to a narrow or wrong context is a common cause of calls that mysteriously will not connect, even when the phone is registered fine. If a Softphone is online but some dialed numbers fail, an over-narrow Exten Context is worth checking.

To see the field this one is paired with, read about what the Phone Context field does, and to see how Phone Context is used to lock a phone down, see how to stop agents dialing outside a campaign. The VICIdial phones guide walks through every phone field together.

Getting dialplan contexts right by hand is fiddly, and a wrong value here is hard to spot. A managed VICIdial host ships with these contexts already wired so the dialer just works. See VICIfast pricing to see what a hosted dialer sets up for you.