Universal Trace Analyzer
Error codes › Q.850 cause

Q.850 cause 20 Subscriber absent

Q.850 causeITU-T Q.850 Table 1

What it means

The subscriber is registered but currently absent (Subscriber absent) -- similar in spirit to a mobile-network absentSubscriber, but at the ISUP/PSTN level.

Where you see it

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

What to check

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

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Related codes

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