[Asterisk-Users] Dialplan question - doesn't quite work - more info

[DB]

Below is a section of my extensions.conf. As you can see I am trying to 
route an incoming call to a remote phone number if it isn't picked up 
within 15 seconds locally. Now this basically works.. the call is routed 
to the remote number. But often it will still timeout and go to 
voicemail.. as if Asterisk thinks the remote call did not connect - and 
this interrupts the call. Sometimes however the voicemail does not kick 
in and it works fine. The rxgain and txgain settings may be having some 
effect but I'm not certain. Does anyone have any advice?


exten => s,1,Answer
exten => s,2,playback(thx4call)
exten => s,3,Dial(Zap/1|15) ; Calls  channel 1
exten => s,4,playback(trying_bert)
exten => s,5,Dial(Zap/4/2326933|15)
;exten => s,5,Dial(Zap/4/12168810880|15)
exten => s,6,Voicemail,u100
exten => s,7,hangup
exten => s,104,Voicemail,b100
exten => s,105,hangup
exten => s,106,Voicemail,u100