[from-jc-custom]
exten => _2XX,1,Set(PJSIP_MEDIA_OFFER(audio)=!all,g722)
exten => _2XX,n,Set(PJSIP_SEND_SESSION_REFRESH()=invite)
exten => _2XX,n,Dial(PJSIP/525${EXTEN},,b(gosub-jc-custom^s^1))
exten => _2XX,n,Hangup()

[gosub-jc-custom]
exten => s,1,Set(PJSIP_MEDIA_OFFER(audio)=!all,g722)
exten => s,n,Set(PJSIP_SEND_SESSION_REFRESH()=invite)
exten => s,n,Return()