Complex sentence: The Number One Electronic Switching System (1ESS), the first large-scale stored program control (SPC) telephone exchange or electronic switching system in the Bell System, was introduced in Succasunna, New Jersey, in May 1965.
Split into simpler sentences: The Number One Electronic Switching System (1ESS) was the first large-scale stored program control (SPC) telephone exchange or electronic switching system in the Bell System. It was placed into service in Succasunna, New Jersey, in May 1965.