There are times when you want to record one or another phone conversation so later could listen again. Don’t know if this is necessary to do, but if so, here is a standalone phone conversation recorder project based on PIC microcontroller. Device is powered from USB and actually sends voice data to computer where software compresses audio to MP3 format for compact storing.

Device automatically detects when phone is picked up so could start recording automatically and stops recording when phone is hanged.

This phone recorder is robust enough to set and forget. PC software is simple but pretty informative where you can see the duration of conversations and other statuses like WAV conversion to MP3. Once you need to listen to record, just go to directory and select one you need. Be sure not to violate the human rights with this.