> ## Documentation Index
> Fetch the complete documentation index at: https://docs.comforthub.app/llms.txt
> Use this file to discover all available pages before exploring further.

# How extensions and personal lines work

> The two ways a caller rings one person instead of a queue, and where the call goes if nobody answers

export const Touches = ({systems}) => <p>
    <strong>Systems involved:</strong>{" "}
    {systems.split(",").map((s, i) => <span key={s}>
        {i > 0 ? " · " : ""}
        <a href={"/systems/" + s.trim()}>{s.trim().replace(/-/g, " ")}</a>
      </span>)}
  </p>;

<Touches systems="twilio, supabase-backend, the-7am-app" />

A caller reaches one agent two ways: by pressing star on the main menu and dialling an extension, or by calling that agent's own number. Either way one app rings, for 25 seconds, and an unanswered call becomes a voicemail.

## Dialling an extension

Star is the one key no department can own. Press it during the greeting and the line says **Please enter the extension, followed by the pound key**. The caller types the extension and pound, and the agent's app rings.

The extension has to name exactly one person who is an active phone agent. Two people sharing an extension resolve to nobody rather than to a guess, and so does an extension nobody holds or that belongs to an agent who is switched off. All three sound the same to the caller: **Sorry, that extension is not in service**, and back to the menu. That counts as one of the menu's three tries, and after the third the line says goodbye and hangs up.

## Calling a personal line

A second number on the Twilio account can have an agent as its owner. A call to it rings only that owner, before any other check, so it rings even while the closed switch is on. The menu does not play and the queues are not offered. A message left there is filed under that line, not the main one.

A call to a personal line is not recorded, and the caller is not told it might be.

## Where an extension comes from

An extension lives on the agent's app user record. Nobody sets their own, and no screen in the app or in Zoho sets anybody else's: a developer writes it in the engine. The agent sees their own under **Profile** in the app, and the office reaches them on it once it is there.

## Related

* [How the phone works](/handbook/phone/how-the-phone-works)
* [Roles and what they can do](/handbook/app/roles-and-what-they-can-do)
* [Twilio](/systems/twilio)