© 2017 Digitrax, Inc.
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11.0 Setting Up Locos & Other Rolling Stock for
Transponding
1.
Your locomotives or other rolling stock that you want to use for transponding
must be equipped with either a transponder device or a decoder with Digi-
trax transponder capability included. Transponder devices such as the TD1
& TL1 can be added to non-transponding decoder installations. These de-
vices are very small and easy to install. If you have not put decoders in your
locos, it is easy to use a transponder equipped decoder and then you won’t
have to add a second board inside the loco. All Digitrax current production
decoders support Digitrax Transponding.
2. When you install a wired transponder equipped decoder, you should also
install a load resistor of between 270 ohms & 470 ohms between the blue and
white decoder leads. If you are using a board replacement, and some other
decoders the resistor may already be installed on the decoder. Digitrax com-
patible transponder current pulse generation uses the F0F decoder function
or white lead that is also used for the forward light function. Transponding
will not affect the operation of the forward light but you may see a slight glow
when the light is turned off because of the way transponding works.
Notes: If the resistor is not connected between the blue & white/F0F leads,
then the locomotive will transpond in only one orientation on the track. If
you are using a DH126D, DH166D, TD-1 or TL-1 to equip your loco or rolling
stock for transponding, you won’t need to install the resistor because it is
already included in the decoder.
3. Enable transponding in the transponder equipped decoder by programming
CV61 to a value of 02.
4. Place the loco on the track, select it and run it back & forth. Verify that
transponding is working in that orientation. If transponding is not working,
be certain if required that the resistor described in step 2 above is installed
properly between the white and blue leads of the decoder.
5. Pick up the loco and turn it around on the track, select it and run it back
and forth again. Verify that transponding is working in that orientation. If
transponding is not working, be certain that the resistor described in step 2
above is installed properly between the white and blue leads of the decoder.
NOTE: Locos must be selected in the system for transponding to work.
12.0 Occupancy Debug
Use the LT5 provided or attached LED indicator panel with your BXP88 as
described in Sections 10.2 & 10.3. The LT5 tester or and attached LED indicator
panel allows you to easily check the zone sensitivity (typically 22 Kohms to give
detection). This also aids in the determination of detection number and activi-
