Newbridge 90-2517-32/J 3600 MainStreet WAN switching Telecom System Card / Module

The Newbridge 90-2517-32/J is an eight-port E1 circuit emulation card for the MainStreet Xpress 36170 ATM switch, presented on 120 ohm balanced interfaces. Circuit emulation is what allows a traditional 2Mbit/s E1 leased line or PBX trunk to be carried transparently across an ATM network: the card segments the constant bit rate E1 stream into ATM cells at one end and rebuilds it with its original timing at the other, so the equipment at each end behaves as though it were connected by a real E1 circuit. That was the mechanism operators used to migrate legacy TDM services onto an ATM backbone without replacing customer equipment. The 120 ohm balanced presentation is the European twisted pair convention, distinct from the 75 ohm coaxial variant sold in the same series. Alcatel purchased Newbridge Networks in February 2000, and the platform continued under Alcatel part numbering. Tech-Star, UK-based and shipping worldwide, supplies Newbridge cards for legacy ATM maintenance.