[Asterisk-Users] Zap channel is never realised

[Juanjo Portela]

Dear Sirs,

I have an Asterisk box with two X100P one connected to the PSTN and
the other one with a conventional PBX.
When the asterisk pass a call from the PSTN to the PBX (making a zap
channel bridge) the Zap channel is never realised. Neither when the
PSTN hangups nor when the PBX hangups.

What is going wrong?

Here I attach part of my extension.conf file

exten => s,1,Answer
exten => s,2,Background(bienvenida-es)
exten => s,3,Dial(SIP/Phone4&SIP/Phone3&Zap/g1/5&Zap/g1/4,20,tr)
exten => s,4,Voicemail,u3
exten => s,5,Hangup
exten => s,105,Voicemail,b3
exten => s,106,Hangup

Thank you in advance,
Juanjo