4452d530_able___FreeSWITCH___Confluence__Description
[ITU-T Q.850 Code] 30 [Enumeration] RESPONSE_TO_STATUS_ENQUIRY [Cause] response to STATUS INQUIRY [Q.850] [Description] 
This cause is included in the STATUS message when the reason for generating the STATUS message was the prior receipt of a STATUS INQUIRY.
Hangup Cause Code Table - FreeSWITCH - Confluence
Description