Chapter 1. Introduction
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Dual DSU-DP User Manual
3
DDS Overview
Digital Data Service (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 Inter-LATA to an interexchange carrier.
In DDS mode, the Dual DSU-DP supports all DDS
service rates yielding DTE rates of 2.4, 4.8, 9.6, 19.2, and
38.4 (sync or async); and 56 and 64 kbps (sync only).
An additional rate of 57.6 kbps is available in async
mode. At the service rates of 56 kbps and 64 kbps, the
unit can be configured to run slower DTE rates (async or
sync).
Switched 56 Overview
This switched Digital Data Service allows customers to
pay for data connection only for the time the circuit is
connected. The regional operating companies or
interexchange carriers provide the service to SW56
customers. In SW56 mode the Dual DSU-DP supports
DTE rates of 2.4, 4.8, 9.6, 19.2, and 38.4 (asynchronous
or synchronous), and 56 kbps (synchronous). An
additional DTE rate of 57.6 kbps is available in async
