OPERATIONPolar Pattern
Bidirectional, noise canceling
Voice TransmissionElectrical Characteristics
1. Hold the microphone comfortably in the hand positioned so
that the Top-Talk Sound Channels? at the top of the case are Operating Voltage
near the mouth.The clearest sound is often obtained with the
8 V12 V28 VNotes
microphone at the corner of the mouth, with the cable away
Audio Output Level*Audio trim-
from the face.(100 ?bar acoustic-11.5 dBV-11.0 dBV-10.0 dBVpot in factory
test signal at(266 mV)(281 mV)(316 mV)preset posi-
2. Depress the push-to-talk button and make sure the equipment 1 kHz, 10 mm)tion
is in the transmit mode before speaking.
DTMF Output Level-12.8 dBV-12.0 dBV-11.2 dBVDTMF trim-
(230 mV)(250 mV)(275 mV)pot in factory
Dialingpreset posi-
1. Press and hold the push-to-talk button.tion
Dc Supply Current**6 mA12 mA36 mA
2. Press the desired keypad buttons in sequence.A high-pitched
tone will confirm that the code has been transmitted. (The *Standard electrical test circuit per RTCA DO-170
microphone audio is muted during DTMF tone transmission.)**Microphone is powered only while PTT switch is depressed (standby
current = 0 if PTT switch is released)
Operation of microphone and DTMF functions requires that the
Environmental Conditions
AM8T be connected to the communications equipment and that
Operating Temperature: -40 to 60° C (-40 to 140° F)
the equipment power is turned on.
Storage Temperature: -54 to 85° C (-65 to 185° F)
After connection to the communications set, turn the equipment Relative Humidity: 0 to 95% (non-condensing)
power On. Pressing the push-to-talk switch and observing the key-Microphone Connector
pad LED backlighting can verify power application.6-conductor modular telephone type
PTT Switch Assembly
Factory preset microphone audio and DTMF levels are correct
Mechanical: Double-pole, single-throw, leaf-type, normally open
for aircraft radios with standard input circuits (as defined in RTCA
Cable
DO-170), and level adjustment should not ordinarily be necessary. ?
ALM-88, detachable MODULINK, 1.8 m (6 ft) extended cord
When such adjustment is necessary, it should be performed only
with modular plug on microphone end and PJ-068 aircraft con-
by Shure Incorporated or by an FAA Approved Service Facility.nector on equipment end; and ALM-89 with A4M type connec-
tor.
Use the supplied screwdriver to adjust the microphone sensitiv-
Construction
ity and DTMF output levels as follows:?
Case: Black textured high-impact ARMO-DUR
?
1. Microphone sensitivity: Press the push-to-talk button and Switch Button: Black ARMO-DUR
Keypad: Molded silicone rubber
speak normally into the microphone while checking transmitter
Dimensions
modulation.Adjust the microphone sensitivity control (case
See Figure 2
back, hole ?B? in Figure 4) and repeat the talk test as required.
Net Weight (including cable and connector)
2. DTMF output: Press and hold the push-to-talk button. 283 g (10 oz)
Depress and hold down a keypad button for a continuous
tone. Adjust the DTMF output control (case back, hole ?C? in Replacement Parts
Figure 4) as required.
Modular plug-cable with PJ-068 plug assembly..ALM-88
A4M type connector............................................ALM-89
SPECIFICATIONS
TypeFurnished Accessories
Electret condenser, noise canceling, with transistor pre-amplifi-
Screwdriver.........................................................80B498
er, DTMF signaling circuitry, illuminated keypad
Frequency Response
200 to 4,000 Hz (see Figure 1)Optional Accessories
Mounting Bracket (3 in kit) ..................................RK6MB
+10FAA Certification
The Model AM8T is FAA Certified for aircraft use under FAA
0TSO-C58a requirements. To maintain this FAA Certification, any
dB
service required for the Model AM8T must be performed by Shure
?10Incorporated or by an FAA Approved Service Facility.
2050100200500 1,0002,0005,000 10,000 20,000
Hz
TYPICAL FREQUENCY RESPONSE
FIGURE ONE
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