Specifications

The operator can help provide good commun~cations
by remembering these factors:
1. Keep vehicle windows closed to minimize out-
side noise while transmitting.
2. Bear in mind that passenger conversation or
other in-vehicle noise (radio, air conditioner, etc.) will
be transmitted.
3. Remember that higher vehicle speeds mean
higher background vehicle noise.
4. As with any communications system, care in
speaking clearly will promote intelligible communica-
tion.
SPECIFICATIONS
MICROPHONE
Type:
Dynamic
Frequency Response: 200 to 5,000 Hz (see Figure 3)
d
-
+I0
W
$ O
W
5 -10
L
20 lpO0 lO.000 24000
FREQUENCY IN HERTZ
TYPICAL FREQUENCY RESPONSE
FIGURE 3
Microphone Impedance:
190 ohms at 1 kHz
Output Level (at 1,000 Hz):
Open circuit voltage
(without amplifier)
.......... -79.0 dB
(0 dB = 1 volt per microbar)
Power Level
................ - 58.0 dB
(0 dB = 1 milliwatt per 10 microbars)
Phasing: Positive pressure on diaphragm produces
positive voltage on pin 2 of connector (see Figure
4)
/ CODED TERMINAL
& MICROPHONE WIRING DIAGRAM "I
FIGURE 4
Operating Conditions:
Temperature ... -40" to +74"C (-40" to +165"F)
Relative Humidity .................... .5 to 95%
Cable: Non-detachable 1.8m (70 in.) two-conductor
shielded plastic-jacketed cable
Connector: Two-pin male miniature audio*
Finish: Dark gray
Dimensions: See Figure 5
....
(72 IN.)
MICROPHONE OVERALL DIMENSIONS
FIGURE 5
Net Weight: 98 grams (3% oz)
AMPLIFIER
Voltage Gain
(at 1,000 Hz): Adjustable, 38 to 59 dB
Frequency Response: 200 to 10,000 Hz as shown in
curve 4-5 of Figure 6
AMPLIFIER FREQUENCY RESPONSE
FIGURE 6
Output Clipping Level:
1V min. (100-ohm output ter-
mination)
Recommended Load Impedance: 100 ohms min.
(superimposed dc voltage up to
16V will not affect
operation)
Output Impedance: Less than 10 ohms
Phasing:
Output is out of phase with input
Noise (300 Hz - 20 kHz): - 11 8 dBV
(equivalent input noise at full gain)
Total Harmonic Distortion (at 1,000 Hz): 3% max. at
500
mV output
Current Drain:
15 mA max. (no signal)
25
mA max. (100-ohm load, 750 mV output)
Operating Voltage: + 10.0 to +I59 Vdc, negative
ground
Fuse: 5A, 32V, 3AG
Operating Temperature Range:
-29" to +74"C (-20" to 165°F)
* Designed to mate with Switchcraft "Slim Line II" or equiv-
alent connector.
3
Dimensions: See Figure 7