Feature Code
A feature code is a short dial sequence, often starting with a star, that tells the PBX to perform an action such as enabling call forwarding, Do Not Disturb or checking voicemail.
Published 8 November 2026 · Updated 9 November 2026 · 1 min read · By SpaGreen Creative
Short answer
A feature code is a short dial string, usually prefixed with * or #, that a PBX interprets as a command to toggle a service such as call forwarding, Do Not Disturb or voicemail access.
Feature codes let a phone control PBX services without a dedicated interface. You dial a short sequence, the PBX recognises it in the dial plan, performs the action, and usually plays a confirmation tone or announcement. Common examples on Asterisk-based systems such as FreePBX and Issabel include *72 to enable unconditional call forwarding and *73 to disable it, *78 and *79 for Do Not Disturb, *90 and *91 for forwarding on busy, *52 and *53 for forwarding on no answer, and *97 to reach your own voicemail. The exact codes are set by the administrator and are listed in the PBX under its feature code settings.
From the softphone's point of view, a feature code is an ordinary call. The app dials the digits, the PBX answers and acts, and the call ends. The behaviour therefore depends entirely on the server; a code that does nothing usually means the PBX uses a different sequence or has the feature disabled.
SIPdia uses feature codes to implement call forwarding and Do Not Disturb. The defaults match the common Asterisk values listed above and can be edited per account under Settings > Feature Codes to match your PBX. Forwarding and Do Not Disturb are part of SIPdia Premium.
Sources and further reading
- Asterisk documentationdocs.asterisk.org
This article is published by SpaGreen Creative, the maker of SIPdia. Product names mentioned belong to their owners. Where it describes other software, treat the steps as general guidance and check the official documentation linked above.
