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INSTALLATION & OPERATION

The base unit is installed by connecting a phone line to an RJ11 wall jack. You can plug a telephone into the jack. Power can be supplied to the base unit with the wall plug power supply or a USB cable plugged into a PC’s USB port. (I used the power supply that came with the Freescale Wireless Design Challenge contest kit.) A speaker is plugged into the speaker jack. A set of unamplified computer speakers is sufficient for this purpose.

Now let’s focus on the processes of powering up and programming the system. Programming is necessary at power-up. The base unit uses a built-in speech synthesizer to guide you through the programming process. It asks for a network number and security code for dial-up access to be programmed with the push buttons on a Freescale MC13192-EVB. The purpose of the network number is to allow more than one system to work without each reacting to the sensor messages from the others. The base unit won’t act on messages unless the data packet is properly formatted and the network number matches. The network number must be the same for the base unit and all of the remote sensors that the base unit monitors. At this point, the unit will announce that the system is ready to use.

The unit lights LED4 on the MC13192-EVB when a remote sensor reports an error condition. You can press S1 for a summary report from the speech synthesizer. The system plays a message, “Everything is OK,” when the remote sensors don’t report errors. It mentions errors if they occur. For example, if a garage door sensor programmed as device number two senses an open door, the system says, “Garage door two is open.” You can press S2 for a full report, which sounds something like, “Garage door one is closed. Garage door two is open. Temperature sensor one is OK. Water level sensor one is OK.”

When you’re away from home, you can check the status of the system by calling the phone line attached to the base unit. After several rings the base unit will pick up the phone line and ask for your security code. You’ll then enter your code (programmed during the setup phase) using the touch-tone buttons on your phone. The system will time out and hang up the line in 10 s if you don’t respond to the prompts; it will hang up if you enter an incorrect code.

When you enter the correct code, the system automatically provides you with a short summary report. After that, the system tells you to press 1 for the full report or 2 to terminate the call. If you press 2 or don’t respond to the prompt in 10 s, the system says “goodbye” and hangs up.