5ESS(R) ISDN Evolution (2-12) (NOT PUBLISHED)

With the installation of the 5E4(1) generic at Oakbrook, Illinois in 1986, the 5ESS(R) Switch provided a proprietary realization of ISDN based on Alternate Mark Inversion (AMI) coding of the level 1 ISDN protocol. In 1988, the ANSI Standard for ISDN DSLs was finalized by the T1D1 committee. AT&T strongly supported this important definition work. With the introduction of the 5E6 generic, the 5ESS(R) Switch will support both the existing proprietary AMI equipment and the new ANSI Standard for U-DSL ISDN.