Number 5 Electronic Switching System

(communications)   (5ESS) An electronic circuit switching product sold by Alcatel Lucent (formerly Western Electric/AT&T Network Systems/Lucent Technologies), used by many telephone exchange carriers and service providers. Succeeded the Number 4 Electronic Switching System (4ESS) and reached widespread use in the 1980s.

Not to be confused with the Class 5 Switch.

Last updated: 2013-09-14