Step 3: Install Door Key, if applicable1. This is a two wire connection fro the monitor to the door key.2. Run positive (+) from the door key to the positive (+) on the monitor.3. Run negative (-) from door key to the negative (-) on the monitor.Step 4: Use the Unit1. Connect power to the system, push the button on the camera and wait for a response fromthe monitor.2. Pick up the handset to respond to the outside camera when talking.