Add echo for caller to Asterisk Application

We have a small Asterisk application which modifies the voice of the caller while making a call. Currently, the caller only hears the voice of the called party, and the called party hears the modified voice of the caller. We want to modify the code so that the caller will hear both the voice of the called party and his own modified voice. Please quote and I'll provide the Asterisk source code to be modified. Our Asterisk version is 1.2.13 on a Debian. Thanks, ## Deliverables 1) All deliverables will be considered "work made for hire" under U.S. Copyright law. Employer will receive exclusive and complete copyrights to all work purchased. (No 3rd party components unless all copyright ramifications are explained AND AGREED TO by the employer on the site per the worker's Worker Legal Agreement). ## Platform Our Asterisk version is 1.2.13 on a Debian.