Configured 2432 FXS to do hookflash features using this guide https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/sip/configuration/15-mt/sip-config-15-mt-book/voi-sip-hookflash.pdf
The expectation is that when a hookflash signal is received on a FXS port, the IAD would generate a sip reinvite to the PBX with eg sendonly, that would effectively place the call on hold. However, in my tests, upon receiving a hookflash event, the IAD instead generates a sip notify request with body "event flashhook" to the PBX which basically just responds with 200ok and does nothing. Note the PBX in this case is BroadSof
