All you need is a phone line! All phone lines have a constant flow of voltage, around 40-70 volts (up to 100 volts when it rings!), but you can't just plug stuff into it and expect it to work.
Children older than 5 and more than 40 pounds must ride in a booster seat until the child is 8 years old or is taller than 4 feet 9 inches. Anyone over the age of 8 must be protected by a safety belt.
Many states have laws requiring booster seats for kids up to 8 years old and 80 pounds (36 kilograms), or 4 feet 9 inches (about 150 centimeters) tall. Choose a seat with a label that states that it meets or exceeds Federal Motor Vehicle Safety Standard 213.