In 1975 a vending manufacturing company was the first to produce phone card. The first prepaid calling card was put by Italian company in the market in 1976.
These calling cards are made from a magnetic thin strip. They made this magnetic thin strip to replace coin payphone because this coin pay phone usually destroyed, vandalize and stolen. They change this magnetic thin strip because it usually jammed the machine. With the modern technology this magnetic strip was improved and more convenient to use. These are the magstripe we used today.