MIL-DTL-38449D
3.7.1.3 Signal sensitivity (no advance). A signal input of 5.0V or less (classes 1 and 2) and 4.0V
or less (classes 3 and 4) applied to pin F/6 shall not advance the signal pulse amplifier position
(see Figure 2).
3.7.1.4 Signal sensitivity (fire thru). The unit shall advance from READY through CONTACT
to DISCONNECT with a steady input signal voltage of 7.5V dc or greater on pin F/6.
3.7.1.5 Reset. The amplifier shall be reset whenever the voltage is removed from pin A/1 for 50
milliseconds or longer. The presence of a steady dc voltage of up to 4.5V for classes 1 and 2 or
3.5V for classes 3 and 4 on signal input circuit pin F/6 shall not prevent reset.
3.7.1.6 Response time. Upon receipt of a single input pulse as described in 3.7.1.2, the required
change in output (Table 1) shall occur within 50 milliseconds maximum. Upon receipt of a fire-
thru signal, the unit shall advance from the READY to DISCONNECT condition in not less than
50 milliseconds and not more than 200 milliseconds under all operating conditions. These time
requirements shall be met over the supply voltage range noted in 3.7.1.1. This is demonstrated
during the high- and low-voltage functional tests in accordance with 4.4.3.
3.7.1.7 False operation. The unit shall incorporate circuitry in the signal input for damping
coupling coil oscillations. The circuit shall prevent multiple sequencing from a single pulse
command. Signal output lines (C/3, D/4, E/5, G/7, H/8, and J/10) shall be protected against
application of reverse polarity voltages. Protection devices shall be rated at 3 amperes or greater.
The signal output diodes shall be tested during production for their proper characteristics (pin 10
has no output for class 4; see 3.5.1.8).
3.7.1.8 Current consumption. A current consumption of 175 milliamperes under no-load
conditions shall not be exceeded with the input voltage ranging from 18 to 30V under any of the
operating conditions specified herein.
3.7.1.9 Alternate power supply (classes 3 and 4). Circuitry shall be provided so that, when
power is removed from pin 1 and applied to pin 11, the intercommunication amplifier shall be
energized and the signaling amplifier shall be de-energized.
3.7.2 Compatibility. The units shall function properly when coupled together by induction coils,
with maximum misalignments and air gaps as specified by the paragraph entitled, Induction Coil,
of MIL-R-27521. Construction of coils shall be as shown on Figure 3 or as approved by the
procuring activity.
3.7.3 Interference control. The units shall meet the requirements of MIL-STD-461; however,
the relays shall be exempt from the requirements.
(A) TANKER COIL DESIGN
1. The coil shall be made of 2,300 turns #38 B and S Formex magnetic wire or
equivalent with the resistance of 333 to 432 ohms.
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