Hello everybody, we are currently having problems with incoming calls on our 3CX. We have a Grandstream GXW4104. We have also configured an extension # of 124 (registered to a GS GXP2020 feature phone). Also, port #1 of the Grandstream GXW4104 is connected to a PSTN line and is registered to the 3CX with a virtual extension # of 10009. Calls to port #1 (virtual extension 10009) are set to "CONNECT TO EXTENSION" # 124 under the PSTN DEVICES > EDIT GATEWAY > EDIT PORT SETTINGS. Here's the problem, if local 124 is currently talking to another local (extension) #, external callers passing through the VoIP gateway on port #1 (virtual extension 10009) that are supposed to be forwarded to extension # 124 still has ringing signal instead of a busy signal. Is there any way for the external caller to hear a busy signal instead of just ringing? Because callers might think that their calls are not being attended to. Thanks in advance.