Simplify the following text for a Grade 9 native English-speaking person.
Original: Testing of prototypes commenced in December 1993 , and the roll-out of the system was carried out from August 1996 to April 1998 , and acceptance occurred in November 1997 .
Simplified: Testing of prototypes commenced in December 1993 , and the roll-out of the system was carried out from August 1996 to April 1998 .