ADTRAN DSU IV ESP, User Manual

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Chapter 1. Introduction
61204011L1-1 DSU IV ESP User Manual 1-3
DDS Operation Overview
DDS is a nationwide service that allows interconnection and
transport of data at speeds up to 64 kbps. The local exchange
carriers provide the local loop service to DDS customers and may
provide data for routing InterLATA to an interexchange carrier. In
DDS mode, the DSU IV ESP supports 2.4 to 64 kbps DDS service
rates yielding DTE rates of 2.4, 4.8, 9.6, 19.2, 38.4 (sync or async), 56
kbps, and 64 kbps. An additional rate of 57.6 is available in
asynchronous mode. The unit can be configured to run slower DTE
rates (async or sync) over the 56 or 64 kbps service.
Switched 56 Operation Overview
This dial-up, 4-wire Switched 56 DDS allows customers to pay for
data connection only for the time the unit is active. The regional
operating companies provide the 4-wire local loop service to SW56
customers. The DSU IV ESP supports DTE rates of 2.4, 4.8, 9.6, 19.2,
38.4, and 56 kbps (synchronous) and 2.4, 4.8, 9.6, 19.2, 38.4, and 57.6
kbps (asynchronous).