Dynon Avionics EFIS-D100 Installation Guide - Manual (Page 20)

Instrument Installation
3-8 EFIS-D100 Installation Guide
Altitude Encoder Wiring
If your transponder requires parallel Gray
code input, and you wish to use the EFIS-
D100 as your altitude encoder, you will need
to purchase Dynon Avionics’ Encoder Serial-
to-Parallel Converter. Please refer to page 7-
32 for more information on the installation of
this option. The EFIS-D100 outputs its altitude
measurements in one of four standard serial
outputs and is readable by many modern
transponders. The EFIS-D100 will function
properly whether or not this altitude encoder
functionality is used. To use the EFIS-
D100‘s altitude encoder functionality,
simply wire the 2 encoder connections
(GND and Encoder Transmit) from the DB25
connector to their respective connections on your
transponder.
EFIS
DB25
pin# Function Wire color
13
Encoder
serial
transmit
Blue/White
(or black)
21 Ground White
Per ATC/FAA requirements, the serial encoder output
of the EFIS-D100 reports pressure altitude, which, by
definition, is indicated altitude when the baro is set to
29.92. So, when you set your EFIS-D100‘s baro
adjustment to 29.92, its indicated altitude will match
the altitude that is being reported to your transponder.
There are four different serial formats used by
transponders. The EFIS-D100 can output any of these formats. To select which format the EFIS-
D100 sends out its serial encoder output port, you must choose the appropriate format via the
menu system. When the menu system is displayed, push the following sequence of buttons:
MORE > SETUP > MORE > ALTENC. When in the Altitude Encoder Setup menu, you can
toggle the resolution of the output between 10 and 100 feet; this accommodates some
transponders which can input and display altitude in 10 foot increments. In this menu, you can
also select between the four different output formats, which are described below.
Dynon’s supplied EFIS harness has a serial altitude encoder cable which consists of 2
conductors, surrounded by a metal shield and white insulation. Dynon has shipped harnesses
with different colors for Encoder serial transmit line. Determine your connections using the table
above. Connect the Encoder serial transmit to your transponder’s serial input or to Dynon’s
Serial-to-Parallel Converter as described in the Encoder Serial-to-Gray Code Converter
Installation section on page 7-32 in the Appendix.