3.0 LocoNet: The Digitrax Difference!
3.1 System Architecture
System architecture is the biggest difference among DCC sys-
tems. System architecture is the way the components of a DCC
system communicate among themselves. Digitrax LocoNet is a
Peer to Peer local area network (LAN) designed specifically for
model railroad operation. LocoNet wiring is cost effective,
flexible and expandable to accommodate almost anything you want to do with
your railroad today and in the future.
The system architecture used for communication within DCC systems is not
standardized, therefore DCC compatibility encompasses decoders, command
stations and boosters but not throttles and other devices. In addition, devices
that require feedback and other types of signals that are outside the domain of
DCC, such as detection systems and transponding, are not standardized.
LocoNet incorporates both DCC and other technologies that expand the capa-
bilities of your system. Your Digitrax system gives you the best of both worlds
with a system that is compatible with today’s DCC “standards” and also goes
beyond those “standards” to deliver enhanced system performance, multi-for-
mat capabilities and advanced features that are far beyond the scope of DCC.
3.2 Event Driven or Polled?
LocoNet is an event driven network. The command station on LocoNet waits
for input from other components before sending commands to the layout. For
example, if there are 10 throttles on LocoNet and throttle #1 sends a command,
the command station sees it and executes immediately. With a distributed net-
work like LocoNet, new features can be added by simply plugging in new
hardware or software. Since LocoNet is a peer to peer network, devices on
LocoNet can act independently of the command station, too. Feedback is incor-
porated in LocoNet’s communication scheme so you don’t need to wire a sepa-
rate feedback bus.
Other DCC systems typically use polled buses or “networks.” In this case, the
command station must “ask” each of the throttles or other devices in turn: “Do
you have input for me?” The device must wait for the command station to poll
all the devices on the bus before it sends the command. This arrangement can
slow down response times and limit the number of devices that can be handled
by the system as more and more devices are added. With centralized processing
in a master/slave control type system like this, adding new features usually
means updating the command station software when new components are
added since devices can’t operate on the system unless the master command
station knows how to handle them. To add feedback capabilities to this type of
system, a separate feedback bus may also be necessary.
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