calculations on digitized signals the dsp 210 provides the advantages of powerful mathematical computational ability and programmability for tailored operation in a particular application devices besides a dsp may be adopted for use these devices includes processors with associated code or logic configurations or other signal processing apparatus in this embodiment the dsp 210 is configured to perform various signal processing tasks one portion of the dsp 210 is a cas detector 200 configured to monitor for and detect a cas signal sent from the co to indicate upcoming transmission of important information other portions of the dsp 210 are dedicated to standard telephone operations referred to on fig2 as communication systems 212 an echo canceller 216 connects to the conductors that connect the codec 206 to the communication systems 212 of the dsp 210 so that the incoming signal presented to the communication systems is also presented to the echo canceller the output of the echo canceller 216 connects to the cas detector 200 the echo canceller 216 processes the received signal to remove echo portions of the received signal before presenting the received signal to the cas detector 200 the echo canceller 216 taps into the input conductor and the output conductor that connects to the communication system these line taps provide signals to the echo canceller 216 so that it may processes the incoming signal to remove unwanted signal portions from the incoming signal after removing these unwanted signal portions the echo canceller 216 provides the processed signal to the cas detector 200 in one embodiment the echo.