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Power district
is the power wiring, track, components and equipment attached
to that wiring, driven by a single properly isolated booster. The track for a power
district is double gapped on both ends of the district. The BXP88 is used to set up
detection/transponding sections within one power district.
Power sub-district
is the wiring, components and equipment that are con-
trolled from both power bus wires by their own power management device. Each
of the 8 Detection/Transponding sections on the BXP88 acts as its own sub-dis-
trict implementing short circuit and over current protection.
Detection/Transponding Common
is the common return used within a
properly electrically isolated power district for implementing occupancy detec-
tion.
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 districts
and their boosters are connected electrically by a common rail or common power
bus return wire. This method is traditionally used for conventionally controlled
layouts. Whole layout common is not compatible with the BXP88.
Detection/Transponding Section
is a section of track gapped on one or both
rails and connected to an occupancy/transponding detector so that the detector
can sense the presence of a loco (or other specially equipped cars) in that section
of track and identify transponding equipped locos and rolling stock. Traditionally
with BDL168/RX4 combinations Detection sections could be combined inside
Transponding Zones. With the BXP88 each of its 8 Detection Sections act as
both an occupancy and transponding detector. For simplicity, these sections will
be referred to as Detection Sections in this document. Note the BXP88 does not
support detection/transponding within an automatic reversing section.
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 feedback
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 in rolling stock provide information to
transponder detectors installed on the layout tracks. This lets the system deter-
mine in which Detections Section or track 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
