why did they decide to become Amish

technology

It is common for Amish communities to allow the use of telephones, but not in the home. Instead, several Amish families will share a telephone in a wooden shanty between farms. Electricity is sometimes used in certain situations, such as electric fences for cattle, flashing electric lights on buggies, and heating homes. Windmills are often used as a source of naturally generated electric power in such instances. It is also not unusual to see Amish using such 20th-century technologies as in line skates, disposable diapers and gas barbecue grills, because they are not specifically prohibited by the Ordnung.

http://pittsburgh.about.com/cs/pennsylvania/a/amish_2.htm

Amish and technology

Amish people use little technology which causes them to live a different life than most of the rest of the world by having to still use the old methods of work. However, as the rest of the world advances in technology, the  Amish must also advance a little in order to keep up.

The Amish tend to use very little technology in their day to days lives but still need it to connect with the outside world in case of emergencies or global news.

For example, they live without telephones or electricity or cars, none of those rules are written in stone. They choose to live simply and apart from modern society, but they do use some modern conveniences. Some Amish will use a tractor, but take the rubber tires off.

http://hubpages.com/hub/HOW-DO-THE-AMISH-LIVE

The Amish are practically forced by the outside world to use some technology so they can communicate to a certain degree such as electricity is sometimes used in certain situations, such as electric fences for cattle, flashing electric lights on buggies, and heating homes. Windmills are often used as a source of naturally generated electric power in such instances. It is also not unusual to see Amish using such 20th-century technologies as in line skates, disposable diapers and gas barbecue grills, because they are not specifically prohibited by the Ordnung.
http://pittsburgh.about.com/cs/pennsylvania/a/amish_2.htm

The Amish only share one phone in their neighbor hood for if there is an emergency ONLY so if a disaster occurs they can reach the outside world