Simon Collings - RS-232 Interfacing for Receiver Control

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RS-232 Output from the AOR ARD-2

Interface Unit: None (connection is direct)
Note: In the UK a lead is supplied for connecting the ARD-2 to computers having a standard 9-way or 25-way serial port

Standard Connections Used: TXD, RXD, GND, RTS, CTS

Flow Control: Hardware

Type of RS-232 Command Set: ASCII (read only)

Data Parameters: 9600 baud; 1 stop bits; no parity

Overview of ARD-2 Interface

The ARD-2 is AOR's ACARS and NAVTEX decoder. It does not support an RS-232 command set (operation being driven wholey from the unit's front panel), but does output formatted and decoded data via an RS-232 port for reading by a PC or other serial device.

RS-232 connector pinout

ARD-2 9-way	Function	PC 9-way	PC25-way
2	RX data	2	3
3	TX data	3	2
5	GND	5	7
7	RTS	7	4
8	CTS	8	5

ACARS-1 format

ACARS data is output as a continuous stream of formatted ASCII data. When an ACARS signal burst is detected and succesfully demodulated, the signal contents are output to the serial port so that they can either be read by a terminal program on a PC or printed to a serial printer (note: the message content is often preformatted by the sender to fit on an 80 column width printer or display).

Each signal burst corresponds to a record of data with fields for the ACARS mode, Aircraft registration, message label, block identifier, message number, flight identifier and message content. An example ACARS burst output in ACARS-1 mode is shown below:

----------------------------------------------------------------------------
ACARS mode: G Aircraft reg: .G-AWNO
Message label: 10 Block id: 6 Msg. no: 3355
Flight id: BA0095
Message content:-
WAB02CHANGES FM ISSUE 1
BA95/01 01FEB98
LHR YUL GAWNO
.....................
ZFW 217.3
TOW 306.0
PAX 325 PLUS 0
STAB 5.9 UP
LIZFW 545.1
.....................
1145Z 01FEB

EN

ACARS-2 format

ACARS-2 mode is the same as ACARS-1 except that all data except the message content is ommitted. The output data is unformated.

NAVTEX-E and NAVTEX-J

NAVTEX can operate in English or Japanese modes. In either case, data is output unformatted as received. Note: Japanese NAVTEX is normally only transmitted along the coast of Japan; you must have a PC or printer capable of displaying Japanese script in NAVTEX-J mode.