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.
For children who are growing, booster seats a needed in the car. A child under the age of 8, who weighs between 40 and 80 pounds and who is under 4 feet 9 inches tall must have a booster seat when rising in the car. Once the child reaches 8 years of age, weighs more than 80 pounds or stands more than 4 foot 9, a regular seatbelt can be used.