Hello, I am able to compile the PJSIP stack and able to transfer file between two PC's by running PJSUA application. Now I want to read/write Sound Data Frames from/to serial port instead of a microphone/speaker. I hope I can achieve this by changing some portion of "pjmedia" OR "third party software" source. But I have no idea which portion of the code needs to be changed and will it affect any other sections of the library. Please help me by sharing your idea. It will be very helpful if you can reply which portion of the code needs to modified and any changes to important data structures. Thanks in advance Sandeep