Hello thanks for reading my letter i'm studying my second year in Systems Engenieer and i gota do a proyect to pass the anual test and this is the idea

WHEN I TOOK THE PHONE AND I'M GONE TO MAKE A CALL I WANT A PROGRAM THAT COUNT THE SECCONDS OF MY CALL.

how do i listen the Modem or i have tu put a external Modem and listen de com2 port???

CAN ANY ONE HELP ME OR GUIDE ME??? IS THERE A BOOK WHERE I CAN FIND THIS INFORMATION ???
WELL THANK YOU VERY MUCH FOR HELP