If the number is stored in a directory, or dialled with a +, the e164, once set up for your region, will replace/modify the + with a required prefix, that can then be processed with your outbound rules. It is the same as placing a call using your mobile and making use of a +. The only difference is that you have to tell 3CX what prefix to use for each type of call...local, national and international. Have to assume that your 3CX outbound rules are currently able to handle numeric long distance prefixes, so there may not be any change needed, with those .