EQUIPMENT MANUAL 265-16-3 REV. 1.00
265-16-3
CONFIDENTIAL AND PROPRIETARY TO COBHAM
Page 3
3.0
INSTALLATION PROCEDURES, WIRING DIAGRAMS, AND LIMITATIONS
Installation dimensions of the Model 265-005 are shown in Figure 1. The case must be grounded to
the aircraft structure, either directly or through a grounding strap of appropriate width according to its
length. The case is finished with electrically insulating and conductive films. The mounting areas of
the footprint are cleared of the insulating finish so that the conductive finish is exposed.
NOTE: The finish should not be removed because it prevents corrosion.
The Model 265-005 can be mounted in any position. No shock vibration isolators are required.
3.1
ELECTRICAL
Connections to the Model 265-005 Area Microphone Preamplifier are made through a 9-pin “D”
subminiature connector (with interfacial seal for moisture resistance). The mating connector is a
standard industry part. The mating connector part number is Positronic RD9F10GE0 (supplied with
FC7522D contacts). This connector is compliant with military part number M24308/2-1 per
MIL-C-24308.
The Model 265-005 amplifier’s input and output wires should be placed no less than 12 inches away
from any 400 Hz current carrying power lines or lines carrying audio frequency interference onboard
the aircraft. This will prevent magnetic coupling of AC noise currents into the audio lines.
Twisted and shielded wire must be used for the audio connections from the microphone to the amplifier
and from the amplifier to the transmitter and/or interphone amplifier. AWG 22 to 26 wire size is
recommended.
NOTE: Audio cable shields must be grounded at one end only. If audio cable shields are grounded at
both ends AC noise currents can flow through the shield and inductively couple noise into the audio
wires. If additional RF shielding is required, use double shielded wire with the inner shield grounded at
one end and the outer shield grounded at both ends.
TABLE 1: P1 CONNECTOR PINOUT
PIN
SIGNAL
PIN
SIGNAL
1
SPARE
6
28VDC RETURN (GND)
2
+28VDC IN
7
SPARE
3
N/C
8
N/C
4
AUDIO OUTPUT HI
9
AUDIO OUTPUT LO
5
AUDIO SHIELD (CHASSIS GND)
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