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Security element
is the plant, including track, associated with any reporting,
interlocking and/or signaling for that track section.
Whole layout common
rail is a method of wiring layouts where power dis-
tricts and their boosters are connected electrically by a common rail or com-
mon power bus return wire. This method is traditionally used for conventional-
ly controlled layouts. The track feeds for one rail are connected together to one
output of the power pack. The other rail is gapped and the track feeds are con-
nected to the power pack through block control switches. Whole layout com-
mon rail wiring has a disadvantage when it comes to detection systems because
detectors are not able to independently monitor whether zone power is on or
off. There is no way to tell whether occupancy detection is actually working in
any given detection section.
Detection Section
is a section of track gapped on one or both rails and con-
nected to an occupancy detector so that the detector can sense the presence of a
loco (or other specially equipped cars) in that section of track.
Occupancy detector
is a device that senses the presence of a locomotive (or
specially equipped cars) in a section of track that is set up for occupancy detec-
tion. Occupancy detectors also provide feedback to indicate occupancy. This
feedback may be in the form of a lamp on a control panel or it may be a feed-
back message sent to the system that can be used by other layout devices. Also
called a block occupancy detector on conventional layouts. Detectors are not
covered by the DCC Standards or Recommended Practices.
Transponder
is an electronic device that is installed in rolling stock and can be
assigned a unique address. Transponders provide information to transponder
detectors installed on the layout. This lets the system determine in which detec-
tion section the transponder is currently located. Transponders are included in
all current production Digitrax decoders and many older models as well. TL1
& TF4 function only decoders with transponding are available as separate units
that can be added to locos with existing decoders or to other rolling stock with-
out decoders if you want to use them for transponding only and don't need
motor control.
Transponder detector
is an electronic device installed in a detection section
on the layout that receives the information broadcast from a transponder. The
transponder detector sends feedback to the system to let it determine the detec-
tion section location of any given transponder at any time. Your BDL168 can
hose one or two RX4s. One RX4 transponder detector can be hosted by a
BDL168; this enables 4 transponder zones on the BDL168. In this case, each
transponding zone may encompass one to four detection sections. Each
BDL168 can host an additional RX4 giving you a total of 8 transponder zones
that can be shared across the available 16 detection sections of the BDL168.
Note When automatic reversing is used there are special considerations in
grouping detection sections and transponder zones within your BDL168.