ADS-B FDL-978 Series and
Lite Series Installation Manual
Document No. 87343 Rev G
FFS Copyright © 2016 All rights reserved.
2-15
The TC978 uses 5.5 – 10 volts from the FDL-978 Lite Series and FDL-978-XVR (typically ~7
volts).
2.7.2 Remote ON
The Remote ON output controls the power to the FDL-978 Lite Series and FDL-978-XVR. This
is connected to the REM ON input (J1-32) to remotely control power to both units.
2.7.3 TMAP Bus
TMAP is a proprietary protocol using RS-485 bi-directional serial bus between the TC978 and
FDL-978-XVR. The TC978 RS-485 lines (TMAPA and TMAPB) are connected to the FDL-978-
XVR RS-485 lines (TRxD3+ and TRxD3-) respectively.
2.7.4 Altitude Out
The TC978 outputs pressure altitude data on this RS-232 serial output pin (ALT_OUT) at 9600
baud using the “Icarus” format (See Section 6.1). The pressure altitude data output depends on
the Altitude input configuration. If an external Altitude/Air Data Input is configured to a FDL-978
Lite Series or FDL-978-XVR ARINC (FDL-978-XVR only) or Serial port, then the pressure
altitude data output from the TC978 will pass through data from that sensor.
If an Altitude/Air Data Input is not configured, then the pressure output defaults to the TC978
built-in altitude encoder. If used, this output should feed the aircraft transponder so they share
the same altitude source.
2.7.5 TC978 Connections
DB-44
TC978 (DB-9)
PIN
SIGNAL
PIN
SIGNAL
J1-18
Vcp
8
POWER
J1-2
GND
1,6,9
GND
J1-32
REM ON
7
REM ON
J1-20
TRxD3+
2
TMAPA
J1-21
TRxD3-
3
TMAPB
