There is a few ways you can interconnect with other system using Asterisk. In this method, since I don't have E1/FXO/FXS card at my Asterisk system. Thus I am deciding to you my existing Cisco Gateway AS5XXX to interact with Asterisk via SIP protocol.
Listed below are the major call feature has been tested by using this kind of setup. 1. Fax to Email (Using E1 DID) 2. IVR (Time Base Routing) 3. Faxing out using Hylafax