Cabletron Systems SmartSwitch SBU128, User Manual

Page: 7 / 76

This is the SBU128
80-10200000-01 1–1
1 This is the SBU128
1.1 Introduction
The SmartSWITCH SBU128 Backup Unit provides an effective, easy to
implement, automatic backup over the ISDN (Integrated Services Digital
Network) for an X.21 or V.35 PTO Leased Digital Circuit (DLC).
The ISDN Basic Rate Interface (BRI) is provided by a public switched
digital network, enabling simultaneous multi-service connection over a
single pipe, consisting of two 64kbit/s data paths and one 16kbit/s control
channel.
The SBU128 is available as a single channel device, but using both
ISDN 64kbit/s ‘B’ channels providing backup on ISDN for the user at
128kbit/s.
The SBU128 is designed to sit in the data path between the PTO DLC
Network Termination Unit (NTU) and your user equipment, see
Figure
1.1 .