Your team

Extensions: short internal numbers for your team

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Watch: Add users and extensions · 2 min · steps and transcript · all video guides

Give each person or phone a 3 or 4 digit extension, assign it to a user, choose the device type, and call each other free anywhere in the world.

Which plans include it

Included on Growth and above. On Free Trial, Entry, Plus you can add it on its own at £2.95 a month from Features & add-ons.

Free Trial
Add-on £2.95/mo
Entry
Add-on £2.95/mo
Plus
Add-on £2.95/mo
Growth
Included
Pro
Included
Enterprise
Included

What it means

An extension is a short internal number (e.g. 204). Calls between extensions stay inside your system, so they are free and work the same whether your colleague is next door or abroad.

What it does

  • Creates extensions (auto-numbered if you leave the number blank).
  • Assigns each to a user and a device type: Softphone, Desk Phone, Mobile or Fax.
  • Labels them, adds notes, and switches them on or off.
  • Makes internal calling and transfers by extension possible.

Every part of the page

Total Extensions
How many are configured.
Extension list
Ext., Label, Assigned To, Device, Status, Actions.
Extension Number
3 or 4 digits. Leave blank to auto-assign.
Label / Name
E.g. "Reception" or "Sarah — Sales".
Assign to User
Links the extension to a dashboard user so it rings their softphone and apps.
Device Type
Softphone, Desk Phone, Mobile or Fax.
Active
Untick to disable without deleting.

How to use it

Give a new starter an extension

  1. Create their login on Users first.
  2. Press "Add Extension".
  3. Leave the number blank (auto) or type e.g. 205.
  4. Label "Priya — Accounts", assign to Priya, Device Softphone.
  5. Save. Priya can now be dialled on 205.

Connect a desk phone (e.g. Yealink)

  1. Press "Add Extension", label it e.g. "Reception desk phone" and set Device Type to Desk Phone. Save.
  2. Open the extension again (pencil). Desk phone settings shows the SIP server sip.siluxcall.co.uk (port 5060, UDP) and the user name (the extension number).
  3. Press "Get desk phone password" and type it into the phone straight away: it is shown once.
  4. On the phone's web page (Account → Register) enter the server, the extension number as Register Name, User Name and Auth Name, and the password. Save: the phone shows Registered.
  5. Add the extension to your hunt groups or menus like any other extension.

Examples

Simple numbering

Reception 200, Sales 201–209, Accounts 210–219. Easy for staff to remember and for callers to be told "ask for extension 210".

Two offices, one system

Staff in London and Glasgow call each other on extensions for free, as if they were in the same building.

  • ★Pick a pattern and stick to it: 2xx sales, 3xx support, 4xx accounts.
  • ★Use 3 digits unless you will ever have more than about 100 people.
  • ★Assign every extension to a user, so its calls reach their apps and voicemail.

Abbreviations on this page

Ext. — Extension
A short internal number (usually 3 or 4 digits) for each person or phone. Calls between extensions are free and never leave your system.
Example: Dial 204 to reach the warehouse.
Softphone — Software phone
A phone that is an app or a browser tab rather than a handset on a desk.
Example: Taking calls on your laptop with a headset uses a softphone instead of a desk phone.
SIP — Session Initiation Protocol
The standard language internet phones use to make and receive calls. Desk phones and apps "register" to your account with SIP.
Example: A desk phone or app signs in to your account using SIP, with a username, password and server address.

Questions

Are calls between extensions free?+

Yes. They never touch the public phone network.

Which plans include extensions?+

Growth and above. On lower plans they can be added on their own as Internal extensions.

Can I use a desk phone?+

Yes — set Device Type to Desk Phone and contact support for the phone's connection details. You can also get them yourself: save the extension as Desk Phone, open it again and Desk phone settings shows the SIP server (sip.siluxcall.co.uk, port 5060 UDP), the user name (the extension number) and a Get desk phone password button. Any standard SIP desk phone works, for example Yealink, Grandstream or Snom. A Desk Phone extension rings only the desk phone, so keep a separate Softphone extension for anyone who also uses the app or browser.

Already a customer? Open this page in your dashboard: Extensions. New to Silux Call? See the plans or start a free trial.

All help topics

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How calls are answered

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