group_confirm_keydtmf digit In the
group_confirm_keyvariable, you define the DTMF that the called party should send to FS to bridge the call. If a wrong DTMF or no DTMF is sent, the called won't be bridged and the wav file will be repeated.
<action application="set" data="group_confirm_key=1" />
group_confirm_file — Specify a sound file to play to leg-B to prompt to dial a confirmation key