SIP 484 Address Incomplete
The number looks incomplete to the system handling it. On a business phone system that normally means the dial plan expects a different digit pattern than the one being dialled, or a required prefix is missing.
What SIP 484 Address Incomplete actually means
The request URI was incomplete and the server expects further digits before it can route the call. It exists to support dialling digit by digit, which is why it shows up so readily where a dial plan and a user disagree about how many digits a number has.
What causes SIP 484 on a business phone system
- The dial plan pattern does not match the number dialledA rule written for eleven digits will treat a ten digit entry as unfinished. Common where staff dial short internal-style numbers for external destinations.
- A required trunk or area prefix is missingWhere the system expects a leading digit to select an outside line, or a full area code, a number without it is judged incomplete.
- The inter-digit timeout is too shortA user dialling from memory with pauses can be cut off mid-number by an aggressive timeout, so the system routes what it has.
How to fix SIP 484
- Dial the number in full national format and retestUsing the complete number with its area code tells you immediately whether the pattern or the number is at fault.
- Review the dial plan patternsConfirm there is a rule matching each length of number your staff genuinely dial, including mobile, national, non-geographic and international.
- Lengthen the inter-digit timeoutWhere users dial slowly, a slightly longer timeout removes a whole class of complaints at no cost.
Fixing the underlying problem
This page explains the code. These guides walk through the fix in detail.
Questions about SIP 484
What does SIP 484 Address Incomplete mean?
Call hangup causes that become SIP 484
If the call crossed a gateway between SIP and ISDN or SS7, this status may have started life as one of these Q.850 cause values. The mapping is defined in RFC 3398 section 7.2.4.1.
Related SIP response codes
Source. SIP 484 Address Incomplete is defined in RFC 3261 section 21.4.22 and registered in the IANA SIP Parameters — Response Codes. The causes and fixes above are drawn from our own experience supporting UK business phone systems.