Chapter 1 Understanding Isdn And The Express L128T S/T; Isdn Overview; The Express L128T S/T - ADTRAN Express L128T S User Manual

Chapter 1

ISDN OVERVIEW

The Integrated Services Digital Network (ISDN) is a public or private
switched digital network. ISDN is an international standard for digi-
tal communications, allowing a full range of enhanced services sup-
porting voice, data, and image applications through standard
interfaces over a single telephone wire. ISDN provides a means of in-
tegrating these services and modernizing communication networks
for information movement and management efficiency.

THE EXPRESS L128T S/T

The Express L128T S/T is a standalone device that links two Local
Area Networks (LANs) using a high-speed ISDN public network or
leased two-wire line. The Express L128T S/T has two plain old tele-
phone service (POTS) connectors used for voice/modem applications.
See Figure 1-1 on page 1-2 for an illustration of the Express L128T S/T.
The 10BaseT connector operates at 10 megabits per second half duplex
and accepts standard Ethernet packets encapsulated using IEEE 802.3
or Ethernet II (DIX). Because the 10BaseT is a four-wire interface, a
crossover switch permits the user to connect to either a hub-concentra-
tor or network interface card without the need for special cabling. The
maintenance port can connect to any asynchronous terminal emulat-
ing a VT 100 terminal for configuration.
61202070L3-20
Understanding ISDN and the
Express L128T S/T
Express L128T S/T User Manual 1-1