Extension Append CID explained

When an inbound call rings an agent, the name shown alongside it, the CID (caller ID) (Caller ID, the name and number that travel with a call), can carry more than just the customer's details. The Extension Append CID setting on an Ingroup (the inbound queue that holds callers until an agent is free) tacks the agent's own extension onto that caller ID name. It is a small touch that helps with on-hook phones and with sorting out who handled what.

What gets appended

Enable Extension Append CID and calls coming in from this in-group get a space and the agent's phone Extension (the internal number that identifies an agent's phone on the system) added to the end of the caller ID name before the call is sent to the agent. The default is N for disabled, so normally nothing is appended and the caller ID name passes through unchanged.

Why would you want the extension stuck on the name? The main case is on-hook phones, where the Agent (a person logged in to take calls) keeps their handset on the hook and the call rings their physical phone. The appended extension on the display tells the agent, or anyone looking at the phone, which extension the call is destined for, so a shared phone or a desk with multiple lines does not get confused about who the call is for.

The USER and WITH_CAMPAIGN options

Two variations change what gets appended. If USER is part of the option, the user ID is appended instead of the phone extension, which is friendlier if your agents are identified by login name rather than a numeric extension. If WITH_CAMPAIGN is used, another space and the campaign ID are tacked on as well, so the caller ID name ends up carrying both the agent identifier and the campaign the call belongs to.

How the name gets built

flowchart TD
  A[Inbound call] --> B{Append CID enabled}
  B -->|no| C[Name unchanged]
  B -->|yes| D{Option flags}
  D -->|default| E[Add extension]
  D -->|USER| F[Add user ID]
  D -->|WITH CAMPAIGN| G[Add campaign ID too]
  E --> H[Send to agent phone]
  F --> H
  G --> H

When it is worth turning on

If your agents use softphones inside the web interface, this setting matters less because the screen already shows them everything. It earns its keep with hardware phones and on-hook setups, or anywhere you parse caller ID name downstream for logging and want the agent or campaign stamped on it. It pairs naturally with the on-hook caller ID controls and the queue routing covered in our inbound call handling guide. For how the system decides which agent the call rings in the first place, see the next-agent-call setting.

Extension Append CID is a niche but useful setting: it stamps the destination extension, user, or campaign onto the caller ID name so on-hook phones and downstream logs know who the call is for. Mind the name length and test on real handsets. If you would rather not stand up the server, our managed VICIdial hosting provisions a working dialer in under a minute.