Circuit Lake

Electronic Project and Circuit Collection

AVR Phone Recorder and Telephony Platform

04/18/2010 Category: AVR, Project

AVR Phone Recorder

This ATmega32-based project describes the implementation of a phone line audio and event recorder originally devised for technical support call center quality assurance purposes. However, it is a reasonably generic telephony platform that can be easily adapted for other applications, such as an answering machine/interactive voice response system; or, doing away with the LCD and SD/MMC card, it could become a low speed modem; or, adding a few relays, it could be made into a remote home automation system. The project is designed by Marco Carnut.

Project Features

  • Works both as a standalone device or in conjunction with a PC
  • Records up to 230 calls or 17 hours of audio with a 512MB MMC/SD card
  • DTMF detection for European-style incoming caller ID and outgoing number detection
  • Allows listening to calls in real time or replaying them later
  • Allows simultaneous record and playback
  • Transmits audio over the serial port either in real time or replaying from the memory card
  • LCD for call progress monitoring and timing
  • Optional “mini-UPS” battery backup allows operation even in case of power failures