Troy Carpenter

I created a conference circuit from discrete components. What it does is answers a call and bridges the call to up to 3 other people. If a caller hangs up, the system will reset on that line and wait for another call. I also set up a timer circuit using the 555 timer chip. All the callers would get disconnected after 8 minutes. I later ran this conference circuit behind a key system, so I designed a voltage drop detector circuit (hangup detector).