Specifications

Watson TDM
Operating Manual
Watson-TDM-Manual-W.doc
Version 2.0-01
2-2
Revision: 2008-02-07
2 Watson TDM Overview
2.1 Introduction
The Watson TDM family is an SHDSL transmission system compliant to ITU-T
G.991.2 [11] and to ETSI TS 101 524 [10].
SHDSL uses pulse amplitude modulation (PAM) with 16 or 32 constellations and
Trellis coding. Multiple linerates as well as 1-pair, 2-pair, and 4-pair DSL trans-
mission are supported.
The Watson TDM modems are available as plug-in cards and as tabletop units.
The plug-in cards normally work as Line Termination Units (LTU, STU-C in [11]).
They can be configured for remote powering of tabletop modems.
The tabletop units normally operate as Network Termination Units (NTU, STU-R
in [11]). Tabletop modems can either be powered remotely from a plug-in modem
or locally with an AC/DC adaptor.
Both plug-in an tabletop modems can be configured either as DSL master (STU-
C in [11]) or as DSL slave (STU-R in [11]).
The Watson TDM Regenerator is used to extend the reach of a DSL link. The re-
generator works in 1-pair and 2-pair modes, is cascadeable for very long links
and is available with a number of housing options. Powering of the regenerator is
either from a plug-in modem or locally.
2.2 Modem Features
The Watson TDM modems are designed to transport E1 or nx64 kbps data sig-
nals.
Multiservice operation: on modems equipped with both E1 and data interfaces
both interfaces can be active simultaneously. In multiservice operation the avail-
able DSL linerate is split between E1/fractional E1 and data services. The time-
slot assignment between the two services is freely configurable.
Multimode operation: it is possible to establish DSL links between modems with
E1 interfaces and modems with data interfaces. The modems will map the nx64
signals on fractional E1 or transparent 2.048 Mbps G.703 signals. No additional
converter is required.
Multipoint operation: the Watson TDM plug-in modems have a built-in cross con-
nect function. In multipoint operation timeslots from several DSL links are aggre-
gated on a single channelized E1 (G.704) interface. Cascading of several multi-
point plug-ins is also possible.