The TCL application is used to handle every VoIP call in Cisco. If you do not configure the specific application on the dial-peer, the DEFAULT application is used. You can replace it with something else. On the site of Porta Software (www.portaone.com, store.portaone.com) there are several advanced TCL applications, “Advanced Remote Authenticate” even contains the translation rule – you can get it and use as an example.