TELCOLINK DT - AccessDSL NTU
User Manual
Version: 2.5
Page 10 of 66
3 CONFIGURATION OPTIONS
The following sections describe the various configuration options. The operating modes for the
NTU are configurable via the V.24 monitor interface on the rear panel as well as from remote
LTU (or NTU) via DSL in case of establishing of the link. The unit has to be configured for local
or remote power switch, placed on the rear panel.
3.1
xDSL
The following two configuration options refer to the xDSL side only and do not affect the E1 and
Nx64/RS232 interface operating mode.
3.1.1 Master / Slave
To start up an xDSL link, one system unit must be configured as master and the other one as
slave, as the link start-up procedure is controlled by the slave. If both system units are
configured as master or both as slave, no start-up will occur.
Normally, the LTU is configured as master (default setting). In addition, it is also possible to set
up an xDSL link with two NTUs, given that one is configured as master and the other one as
slave.
The "Master / Slave" option also affects the EOC related functions. Generally, the master-slave
rights are:
The master unit has local access as well as access to the slave unit. The master / slave,
G.992.1 Annex, Autorestart configuration and some other settings cannot be altered by the
master unit over the xDSL link for safety reasons (thus, default configuration cannot be
loaded remotely, see chapter 7 for details).
LTUs are always delivered as
master
(factory setting).
NTUs are always delivered as
slave
(factory setting).
The slave unit has the far end LED always off, whereas the master unit has it always on.
3.1.2 Normal / Dual pair / Multipoint mode
Units with two xDSL interfaces can operate in 2-wire (Normal) or 4-wire (Dual Pair) mode
according to ITU-T G.992.1. To start up an xDSL link, both system units must be set to the
same mode. Rate adaptation is not supported in Dual Pair Mode, so in this mode both system
units must be set to the same base rate.
In Multipoint mode E1 data is multiplexed to two xDSL interfaces. First n channel time slot is
transmitted through xDSL interface A, while other m channel slots
– via xDSL interface B. There
are two sub-modes: PCM30, when TS16 is processed as signaling slot, and PCM31, when
TS16 is considered as channel slot. Multipoint mode is possible for Master only.
3.1.3 Fixed rate / Adaptive setting
In Normal and Multipoint modes Master can operate either in Fixed rate mode (the link will be
established according to Baserate setting if xDSL line conditions allow it) or in rate adaptation
mode (line rate will be selected automatically due to line conditions). In Normal mode Slave is
always in adaptive mode, thus link will be established according to Master settings.