[helpdesk]
exten => 1000,1,SetVar(attempts=321)
exten => 1000,2,Goto(call-handler,s,4)

[hdeskvm]
exten => s,1,Answer()
exten => s,2,Wait(2)
exten => s,3,Voicemail(u1234@helpdesk)
exten => s,4,Congestion()
exten => h,1,SetVar(attempts=321)
exten => h,2,Goto(call-handler,s,4)
exten => h,3,Congestion()

[helpdesk]
exten => 1000,1,SetVar(attempts=321)
exten => 1000,2,Goto(call-handler,s,4)

[hdeskvm]
exten => s,1,Answer()
exten => s,2,Wait(2)
exten => s,3,Voicemail(u1234@helpdesk)
exten => s,4,Congestion()
exten => h,1,SetVar(attempts=321)
exten => h,2,Goto(call-handler,s,4)
exten => h,3,Congestion()

[call-handler]
exten => s,1,GotoIf($["${attempts}" = "1"]?s|103)
exten => s,2,SetVar(attempts=${attempts:1})
exten => s,3,Wait(60)
exten => s,4,SetVar(ACK=no)
exten => s,5,Dial(Sip/116,20,rgM(vmalert))
exten => s,6,GotoIf($["${ACK}" = "no"]?s|1)
exten => s,7,Hangup()
exten => s,103,Goto(noack,s,1)
exten => s,106,Goto(call-handler,s,1)

[macro-vmalert]
exten => s,1,Background(newmsg)
exten => s,2,ResponseTimeout(10)
exten => t,1,Goto(call-handler,s,1)
exten => 1,1,Wait(1)
exten => 1,2,SetVar(ACK=yes)
exten => 1,3,VoicemailMain(s1234@helpdesk)
exten => 1,4,Congestion()
exten => i,1,Playback(gooodbye)
exten => i,2,SetVar(ACK=no)
exten => i,3,Hangup()