Phone Extension
A short internal number assigned to a user or device within a business phone system for internal routing.
A phone extension is an internal identifier — typically 3 to 5 digits — that maps to a specific user, device, or group within a company's phone system. Employees dial short extensions to reach colleagues without using their full 10-digit number. The PBX handles the routing internally without consuming external lines.
Extensions can be assigned to desk phones, softphones, mobile apps, virtual users (such as a conference room), or ring groups. In a cloud PBX, extensions are created and managed through an online portal. Adding a new employee means provisioning an extension and associating it with their device or app — a process that takes under a minute.
Zonitel extensions include voicemail, call forwarding rules, call recording settings, and caller ID configuration — all manageable per-user. Businesses can also create extension directories so callers can dial by name or department code after reaching the auto attendant.