Altitude Input Interface; Wi-Fi Module Or Maintenance Port Interface - FreeFlight ADS-B FDL-978 Series Installation Manual

Control inputs such as Flight Plan ID (Squawk Code), Call Sign, and mode control (IDENT,
Altitude Inhibit, transmit Standby) are required by the FDL-978 Lite Series. The FDL-978 Lite
Series provides the following three modes to receive control inputs:
1. A Garmin GTX Series transponder can be connected to the GTX-REMOTE Input port
interface on the FDL-978 Lite Series. The FDL-978 Lite Series accepts the control
(Squawk Code and mode) inputs from the transponder. The TC978 displays control
status but Squawk and mode control from the TC978 are locked out. The Call Sign can
be controlled by the TC978 in this mode.
2. When NO GTX transponder is connected to the GTX-REMOTE Input port, the FDL-978-
TX listens for Mode A messages transmitted by an on-aircraft Mode A/C transponder
and sets the squawk code and IDENT to the same code/IDENT being transmitted by the
transponder. The TC978 displays control status, but Squawk and IDENT from the TC978
are locked out. The Call Sign and mode control (Altitude Inhibit and Transmit Standby)
can be controlled by the TC978 in this mode.
3. When the aircraft has no transponder, the TC978 provides all control inputs and status
feedback.
12.12.2.2

Altitude Input Interface

FAA AC 20-165A requires certified installations with ADS-B Out Transmitters
(FDL-978 Lite Series) and any transponder on the aircraft to transmit pressure
altitude data obtained from the same altitude sensor source. Installations must;
therefore, ensure that the transponder and FDL-978 Lite Series receive altitude
data from the same altitude sensor.
The FDL-978 Lite Series requires pressure altitude data input from an altitude encoder. The
FDL-978 Lite Series provides the following two modes to receive altitude data input:
1. An altitude encoder which outputs altitude data per the Altitude Encoder format @9600
baud defined in Section 6.1.1 can provide altitude data to the FDL-978 Lite Series. The
Altitude Data input port (port 4) must be configured to Altitude Encoder input @9600
baud to use this mode.
2. The TC978 internal altitude encoder can provide altitude data to the FDL-978 Lite
Series. The Altitude Data input port (port 4) must be configured to UNUSED to use this
mode.
12.12.2.3

Wi-Fi Module or Maintenance Port Interface

FDL-978-XVRL Transceiver
ADS-B traffic and FIS-B data is output (FDL-978-XVRL only) on the Wi-Fi Module/MPI Port. The
FreeFlight Systems Wi-Fi Module (FWF-125) connects to this port and is used to connect to
various tablet applications (e.g. ADS-B MPI and FFS ADS-B View apps) and display traffic and
weather data. System configuration/status can also be set/viewed through the Wi-Fi Module
using the FFS ADS-B MPI Android Application.
FFS Copyright © 2015 All rights reserved.
ADS-B FDL-978 Series and
Lite Series Installation Manual
Document No. 87343 Rev F
12-13