CUCM has cannot influence in anyway about billing outgoing calls.
FXO must go off-hook in order to dial, and you should be billed only if remote answers.
appreciate your cooperation, the problem is that the FXO goes offhook before the remote party pickup the call, means the charging start even if the remote end doesn't answer.
What I'm trying to tell you, it is normal since the invention of telephone, that a calling FXO goes off-hook, as it is a necessary condition to dial.
For example, when you are home, you lift the handset (this means off-hook) and dial. If no answer, you hang-up (meaning you go on-hook) and are not billed.
So check again with your telco.
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I think im having the same issue but different
Basically I need to make an incoming call from the PSTN -> FXO port ring an inside IP phone but not go OFF-HOOK on the FXO until the IP Phone picks up. The customer wants to ring-no-answer after 5 seconds from the telco to another phone number on the PSTN.