air
avionics
2. System Interconnects and Interfaces
Pin Name
Pin number
I/O
RS-232 Port 1 data out (TXD1)
1.3
Out
RS-232 Port 1 data in (RXD1)
1.2
In
RS-232 Port 2 data out (TXD2)
2.3
Out
RS-232 Port 2 data in (RXD2)
2.2
In
The serial outputs conform to RS-232C (EIA Standard) with a positive and negative output
voltage of at least 5V when driving a standard RS-232 load.
The serial data interface (RS-232) consists of one or two data transfer wires and a ground
connection. As shown in the example below, there shall always be a direct ground
connection between all RS-232 clients.
It is not sufficient that power supply ground in both devices is connected to aircraft
ground, an additional direct ground connection is mandatory.
The use of a twisted pair shielded cable, for example MIL-C-27500-22TG 2T14
, is highly
recommended. With this cable both data wires and the GND reference can be connected
using a single cable.
TRAFFIC SYSTEM RS-232 send data (TX)
TRAFFIC SYSTEM RS-232 receive data (RX)
TRAFFIC SYSTEM Ground (GND)
TRAFFIC SYSTEM POWER (VIN)
DISPLAY SYSTEM RS-232 receive data (RX)
DISPLAY SYSTEM RS-232 send data (TX)
DISPLAY SYSTEM Ground (GND)
DISPLAY SYSTEM POWER (VIN)
-
-
-
-
TRAFFIC SYSTEM WITH RS232 INTERFACE
-
-
-
-
DIRECT GND-CONNECTION VIA SHIELD OR EXTERNALLY IS REQUIRED FOR ALL RS-232 CLIENTS
AIRCRAFT POWER (+)
AIRCRAFT GND (-)
AIRCRAFT GND (-)
AIRCRAFT POWER (+)
1
1
OPTIONAL
THIS SYMBOL REPRESENTS TWISTED PAIR CABLES
Figure 2.3.: Generic RS-232 wiring recommendation between ‘‘Traffic System’’ and ‘‘Traffic
Display’’
The table below contains maximum recommended cable lengths using shielded data cables
for an RS-232 data interface. Exceeding these cable lengths may reduce signal integrity and
therefore the reliability of the data interface.
Data Rate
Recommended Cable Length (meter)
Comment
4800 Bd
30
Standard NMEA 0183 data rate
9600 Bd
15
–
19,200 Bd
7.6
–
38,400 Bd
3.7
–
57,600 Bd
2.6
–
1
for procurement, please visit
http://www.air-store.eu
ATD
·
Installation Manual
·
rev. 3.0
·
2019/05/09
13
