Hello, I'm trying to accomplish the following using a TCL script. I'm using SIP to communicate.  An incoming call has to be transferred to another external destination before the incoming call is connected (200 OK sent). All incoming calls are always transferred, but the destination does not always answer. I'm trying to do this to save on the costs for the incoming calls. Is this allowed? So far, the destination does ring and the incoming call has not yet been answered by us(200 OK not yet sent). But when the destination answers, the call is disconnected. I don't know why, but I'll manage to fix that. I just want to know if this construction is allowed and if there are any rules for this?   Kind regards,   Grant

Hello,
Yes, I knew that, but thanks. 
I've managed to build a TCL script which does exactly what I want. The call is now transferred before the incoming call is actually answered by us. Once the destination answers the call, the incoming call is also answered. 
But I'm still wondering if this construction is allowed by some form of law. As far as I know, usually instead of transferring the call, an announcement is played to the user. Like stating the costs for this call.