Apart from communicating with the outside world, Joe has designed an Arduino-based solution for using the home telephones as an internal home intercom system. Using the intercom is simple, by quickly picking up the handset and replacing it, the intercom cuts out the telephone line and then "rings" the phones in the house, which can then be used to converse with each other. After the internal conversation has finished, the phones are reconnected to the outside line. It also has a rudimentary form of call waiting that alerts intercom users that an incoming call is present, and they can switch to the call. Very clever.
When building your own devices that interact with the public telephone network, be sure to understand the rules and regulations when doing so. To get started with your own intercom system, apart from some quality Arduino-compatible boards. Furthermore, you will need some protoshields to hold the extra circuitry. Consider using our range such as the Terminal Shield for Arduino:
For more information, design guides, circuitry and code - visit Joe's site here.
