Section 1 General Information; Kt 74 Description; Interfaces; Table 1-1. Interface Services - Honeywell BendixKing KT 74 Installation Manual

1.1 KT 74 Description

The KT 74 Mode S panel mount transponder is an ED-73E and DO-181E Class 1
compliant Mode S level 2es datalink transponder, with support for extended
squitter, elementary surveillance and surveillance identifier codes. The KT 74 is
also a DO-260B Class B1S compliant ADS-B out participant. The KT 74 meets the
relevant environmental requirements of DO-160G/ED-14G, and is certified to
ETSO C112d, ETSO C166b, TSO C112d and TSO C166b.
The KT 74 transmitter power output is nominally 240 watts, and the transponder
runs from either 14 volt nominal or 28 volt nominal DC power supply with no
configuration changes required.
The KT 74 transponder responds to both legacy Mode A/C interrogations and to
Mode S interrogations from both ground radar and airborne collision avoidance
systems. In all cases, the interrogations are received by the transponder on
1,030 MHz, and replies are transmitted on 1,090 MHz.
In the Mode S environment, S stands for Select, and a Mode S interrogator can
selectively address a single transponder. This allows accurate position plotting
with lower reply rates, which in turn reduces frequency congestion and
interference. In addition, power consumption by the transponder may be reduced,
and simple datalink services can be supported, such as ADS-B out. It is however
crucial to the reliable operation of the system that each aircraft has a distinct
Mode S address. The Mode S address is allocated by the registration authority for
the aircraft, and must be set when the KT 74 is installed.

1.2 Interfaces

At the rear, the transponder has two Molex style connectors and a single antenna
connector for blind mating with the corresponding connectors in the mounting tray.
The interfaces provide the following services shown in Table 1-1.
Interface
Parallel altitude
input
Serial altitude input
© Honeywell International Inc. Do not copy without express permission of Honeywell.
INSTALLATION MANUAL
89000007
SECTION 1
GENERAL INFORMATION
. Interface Services
Table 1-1
Description of Service
Connection to an external altitude encoder using Gillham
code.
Connection to an external RS232 altitude encoder. Using
serial altitude data allows the transponder to report altitude
with 25 foot (7.62 m) resolution.
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15 Nov 2013