Serial Data Electrical Characteristics - Garmin GTX 33 Installation Manual

EXTERNAL IDENT SELECT (remote IDENT) is a momentary input. Refer to the GNS 480 (CNX80) or
the appropriate GTN 6XX/7XX Installation Manual for remote ident configuration.
EXTERNAL STANDBY SELECT (remote STANDBY) is used when two GTX 33 systems are installed
in an aircraft. Refer to Figure D-4, for the EXTERNAL STANDBY SELECT interconnect. When
EXTERNAL STANDBY SELECT is grounded, ARINC 429 OUT PORT 1 remains active, while PORT 2
is inactive.
When TIS is inactive, the GTX 33 logs onto TIS service when a momentary ground is applied to
P3301-46. When TIS is active, a momentary ground logs off of TIS service. Refer to the GNS 480
(CNX80) Installation Manual, MX20 Installation Manual, or appropriate GTN 6XX/7XX Installation
Manual for TIS configuration.
An AUDIO MUTE SELECT mute switch may be used to control TIS audio alerts. TIS (Traffic) Mute
must be clearly marked with MUTE ON/MUTE OFF or TIS Audio ON/Audio OFF labels. The muting
feature may be enabled through a Multi-Function display. In order to prevent inadvertent muting, the status
of muting must default to "Mute off" upon each power cycle. Refer to the GNS 480 (CNX80) Installation
Manual or appropriate GTN 6XX/7XX Installation Manual for AUDIO configuration.

4.6 Serial Data Electrical Characteristics

The GTX 33 manages support for several equipment interfaces. The GTX 33 can be configured to include
GPS, Airdata, AHRS, EFIS/Airdata, and ADLP 429 inputs, functioning as an ARINC 429 data
concentrator.
The GTX 33 has four ARINC 429 input ports, making it capable of taking altitude, air data, heading, EFIS
selected course and possible future features, and then concentrating it on the ARINC 429 OUT 2 ports for
possible data link applications.
The GTX 33 is designed to feed all outgoing data to the external display via RS-232 data ports.
4.6.1 RS-232 Input/Output
Pin Name
RS-232 OUT 1
RS-232 IN 1
RS-232 OUT 2
RS-232 IN 2
SIGNAL GROUND
SIGNAL GROUND
The RS-232 outputs conform to EIA Standard RS-232C with an output voltage swing of at least ±5 V
when driving a standard RS-232 load. Refer to figures in Appendix D for the RS-232 serial data
interconnect.
When connecting two GTX 33 transponders to a GPS, the unit can only receive RS-232 serial data from
one unit at a time. Use a DPDT switch for connecting both serial data and External Standby Select. Refer
to Figure D-4.
GTX 33 Installation Manual
Page 4-8
Table 4-7. RS-232 Input/Output
Connector Pin
P3301 23
P3301 22
P3301 25
P3301 24
P3301 51
P3301 58
190-00906-00
I/O
Out
In
Out
In
--
--
Rev. F