Cooling Requirements; Electrical Connections; Primary Interface - Pinout - Honeywell BendixKing KT 74 Installation Manual

Limits
Reference Inches (mm)
DIM. A 6.30 (160.0)
DIM. B 6.185 (157.10)
DIM. C 1.56 (39.6)
DIM. D 6.31 (160.3)
DIM. E 1.622 (41.20)
DIM. F 0.423 (10.70)
DIM. G 9.478 (240.75)
DIM. H 0.441 (11.20)

2.4 Cooling Requirements

The KT 74 Mode S transponder meets all applicable ETSO and TSO requirements
without forced air-cooling.
Attention should however be given to the incorporation of cooling provisions to limit
the maximum operating temperature of each unit when the KT 74 is installed in a
typical panel or rack. The reliability of equipment operating in close proximity in a rack
can be degraded if adequate cooling is not provided.

2.5 Electrical Connections

The KT 74 has two Molex edge connectors, one with 24 contacts, which is the
primary interface, and a second connector with 12 contacts which carries signals to
support ADS-B and uplinked TIS-A traffic. A single coaxial connector attaches to the
antenna. In simple installations it is possible to omit wiring for the second connector
altogether.
The Molex edge connector used in the KT 74 is similar to the connector used on the
KT 76A and KT 78A transponders, and the common signals on the primary connector
use the same contact positions and are electrically compatible. The antenna
connector is also compatible. Providing that the wiring is appropriately installed, it is
intended that you can upgrade a KT 76A or KT 78A installation to the KT 74 without
any connector rewiring. Before doing that however, you must check that the wiring for
the existing transponder is in good condition.
2.5.1 Primary Interface – Pinout
Refer to Table 2-1 and Figure 2-2 for the primary interface pinout locations.
© Honeywell International Inc. Do not copy without express permission of Honeywell.
INSTALLATION MANUAL
89000007
Dimensional Limits for Figure 2-1
Reference
DIM. I
DIA J
DIM. K
DIM. L
DIM. M
DIM. N
DIM. O
Limits
Inches (mm)
1.254 (31.86)
0.158 (4.015)
7.00 (177.8)
0.079 to 0.095 (2.0 to
2.4)
0.658 (16.70)
0.298 (7.57)
1.665 (42.30)
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15 Nov 2013