Specifications

Revision: 2010-01-20

3-1

3 Modem Features

3.1 DSL

3.1.1 Linerates and DSL sync rates

Watson Ethernet supports SDSL as specified in ETSI TS 101 524 and ITU-T

G.991.2. The linecode used is TC-PAM 16, the maximum linerate rate per pair is

2'306 kbit/s (36 timeslots with 64 kbit/s each).

The Watson Ethernet plug-in can be configured for the 2004 revision of ETSI TS

101 524, also known as eSDSL (ETSI) or G.SHDSL.bis (ITU-T). G.SHDSL.bis al-

lows for higher symbol rates and a 32-level linecode (TC-PAM 32). The maxi-

mum number of timeslots per pair in G.SHDSL.bis is 89, the maximum linerate

rate per pair is 5'696 kbit/s.

There is some overlap between the linerates attainable in G.SHDSL and

G.SHDSL.bis:

16 TC-PAM

32 TC-PAM

G.SHDSL, ETSI TS 101 524

G.SHDSL.bis, e-SDSL

5'696

Linerate

kBps

192

768 3'8402'304

Figure 3-1: G.SHDSL and G.SHDSL.bis linerates

This means that for certain linerates either TC-PAM 16 or TC-PAM 32 can be

configured in the modem. TC-PAM 16 has the better DSL performance than TC-

PAM 32. However with linerates rates higher than 2.3 MBit/s (36 timeslots) and

TC-PAM 16 the symbol rate over the DSL becomes higher than what was speci-

fied in the original version of TS 101 524. Higher symbol rates mean wider PSDs

which in turn can lead to higher interference to other DSL systems in the same

cable binder, e.g. ADSL, ADSL2, ADSL2+.