This project is developed by Bernard Debbasch and is a winner in Philips design contest 2005. it is really cool and flexible answering machine which allows many things including Media storage, internet access where messages can be sent in form of SMS or e-mails, interfacing to phone line, DSP routines. Answering machine(TAM-TAM) also supports multiuser interface where up to four users can have custom settings.
The whole machine is built around LPC2138 ARM7 RISC microcontroller. Project gives a good demonstration of DSP functions including FSK demodulation, voice playback and record, DTMF tone generation and detection. Concurrently there are also running IP stack and File system management tasks. And still, whole system gives good level of performance. Code blocks are written so that they may be easy reused in other projects. All project files are available for download.