Universal Trace Analyzer
Error codes › Q.850 cause

Q.850 cause 1 Unallocated (unassigned) number

Q.850 causeITU-T Q.850 Table 1

What it means

Unallocated number.

Where you see it

In ISUP/BICC REL messages, 2G/3G DTAP Disconnect, and SIP Reason headers (Q.850;cause=…).

What to check

Confirm the dialed number is correctly formatted and assigned.

Check the cause location (user, private or public network) to see which side released the call.

Got a trace with Q.850 cause 1 Unallocated (unassigned) number? Drop it in the analyzer: it finds the step that really failed first, which node sent the code and what to ask the other side. Captures, test-system PDFs and vendor exports. 5 free analyses a month, no sign-up.

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Related codes

Q.850 cause 2 No route to specified transit networkNo route to the specified transit network -- a routing/configuration i…Q.850 cause 3 No route to destinationNo route to the destination at all -- a routing/configuration issue, n…Q.850 cause 6 Channel unacceptableThe channel selected for the call wasn't acceptable to the far end (Ch…Q.850 cause 16 Normal call clearingNormal call clearing — one of the parties hung up normally after the c…Q.850 cause 20 Subscriber absentThe subscriber is registered but currently absent (Subscriber absent) …Q.850 cause 22 Number changedThe dialed number has changed (Number changed).…