ADS-B FDL-978 Series and
Lite Series Installation Manual
Document No. 87343 Rev G
FFS Copyright © 2016 All rights reserved.
6-1
SECTION 6
SERIAL INTERFACE SPECIFICATIONS
Two data formats may be selected to accept input from external Altitude sensors:
Encoder Altitude – Gray-code to serial altitude converters, etc.
Air Data Computer – To select a data format, refer to Section 3.3.2.
6.1 Altitude Encoder Format
The Altitude Encoder (aka “Icarus”) data format accepts messages with the following
parameters:
Baud:
9600
Parity:
None
Start Bit:
1
Data Bits:
8
Stop Bit:
1
Update Rate: 1 msg/sec
Compatible devices include Rosetta Encoders and Serializers (ARS 50 and ARS 100). The
compatible format for altitude information is the following 10 byte ASCII message:
Byte
0
1
2
3
4
5
6
7
8
9
Contents
A
L
T
1
2
3
4
5
c/r
Some examples include:
'ALT 00000'
0 feet
'ALT -1200'
-1200 feet
'ALT 62505'
62,505 feet
'ALT 05604'
5,604 feet
6.2 Air Data Computer/Sensor Format
The ADC format accepts messages with the following parameters:
Baud:
9600 (default minimum)
Parity:
None
Start Bit:
1
Data Bits:
8
Stop Bit:
1
Update Rate: 1 msg/sec
Air Data messages are accepted when the serial port is set to "ENCODER.” A packet consists
of a set of ASCII message strings. The first character of each packet is an ASCII Start-of-Text
(STX = 02H). The last character of each packet will be an ASCII End-of-Text (ETX = 03H). Each
message string begins with one ASCII character to identify it as an Air Data message ("Z"). The
second character identifies which message it is. The rest of the string consists of one or more
alphanumeric ASCII fields. Each message field ends with a carriage return, line feed (CR =
0D0AH). All numeric fields are ASCII decimal, right justified and zero filled. If the ADC cannot
