CONTROLLED MAGNETICm COMMUNICATIONS MICROPHONE
222 HARTREY AVE.. EVANSTON.
IL.
60204 U.S.A.
@
AREA CODE 3121866-2200
.
CABLE: SHUREMICRO
TWX: 910-231-0048 TELEX: 72-4381
GENERAL
DATA
MODEL
444
SHEET
COMMUNICATIONS
MICROPHONE
The Model 444 is a pressure-operated CONTROLLED
MAGNETIC@microphone. It is specifically designed for
radio communication applications and provides opti-
mum performance from single sideband transmitters
as well as AM and FM units. The response cuts off
sharply below 300 and above 3,000
Hz,
with a rising
characteristic to 3,000
Hz.
This special response char-
acteristic results in optimum speech intelligibility and
audio punch to cut through noise and interference.
i
Microphone Features:
A response tailored for single sideband transmis-
sions
w
A switch for instantaneous selection of Press-to-
Talk or VOX (voice-operated relay control) oper-
ation CONNECTIONS
.
Finger-tip control bar (locking or non-locking ac- Model 444 is designed for use with transmitters or
tion) to actuate microphone and an external relay amplifiers having high-impedance inputs. The
BLACK
or control circuit cable lead is the "hot" conductor for the microphone
circuit: the WHITE cable lead controls an external relav
.
~ong-lifeswitch to satisfy severe requirement of circuit. The shield is common to both the microphone
communication systems circuit and the external relay circuit. The shield should
be securely grounded to the amplifier or transmitter
Adjustable microphone height chassis ground. (See Figure
1
for internal wiring
w
A sturdy, high impact ARMO-DUR@base and mi- diagram of Model 444.)
crophone case
r\
Dependability-under all operating conditions
BLACK
GROUNDED TERMINAL
INTERNAL
CONNECTIONS
SHIELD
7
PRESS-TO-TALK SWITCH OPERATION
NORMAL-VOX OPERATION
6G-3
OF CARTRIDGE
-
Most amateur equipment is wired to use either VOX
(voice-operated relay control) or a Press-to-Talk switch.
Model 444 has been designed to provide maximum
flexibility for both types of operation. VOX or Press-
to-Talk operation may be easily selected by the
Normal-Vox slide switch on the bottom side of the
microphone base near the cable entry.
For Press-to-Talk operation of the microphone, the
Normal-Vox switch should be in the "Normal" position.
For VOX operation, the Normal-Vox switch should be
in the "VOX" position, and the Press-to-Talk switch
must be locked in the On position.
The finger-tip control bar can be used as a locking
m-----
i
\
!\
BLACK
or nonlocking switch. To use as a nonlocking switch,
I
I
;
!
WHITE
FIGURE
1
simply depress the control bar and release after trans-
mission. To use as a locking switch, depress the
PRESS-TO-
TALK
IMPORTANT
Shure Microphone Cables are selected after ex-
haustive tests to insure superior performance in micro-
phones because of low capacitance, superior shielding
properties and unusually long life under severe use.
Cables with plastic insulation should not be sub-
jected to excessive soldering-iron heat. Carefully clean
and tin the conductors and the connections to which
the conductors are to be soldered. The soldering
operation can then be done with a minimum of heat,
thereby avoiding any possibility of damage to the
cable.
\{
----
!:
SHIELD
NORMAL
-VOX
Copyright
1978,
Shure
Brothers
Inc.
27A245
(RJ) (OVER)
control bar and pull it forward. To unlock the switch,
t
SWITCH
-
-
iO1
?-
I,,)
SWITCH SHOWN IN
'NORMAL" POSITION
U.S.
Patent
D-198,850
Printed
in
U.S.A.
move the bar back and release.
YELLOW
j
