Model 450 Series II User Guide
WIRING CONNECTIONS
Refer to Figure 1 and Table 1 below. For unbalanced opera-
tion, the GREEN wire is connected to the audio input, the
WHITE wire is connected to the audio ground, and the
SHIELD is connected to chassis ground. In some cases, au-
dio ground and chassis ground will be the same.
For balanced operation, the GREEN wire is connected to the
positive audio input, the WHITE wire is connected to the
negative audio input, and the SHIELD is connected to chas-
sis ground.
IMPEDANCE SWITCH
PRESS-TO-TALK SWITCH
GREEN YELLOW
1
2
3
LO
HI
BLACK
RED
GREEN
WHITE
BLACK
SHURE MODEL 450 SERIES II
SHIELD
PAGING AND DISPATCHING MICROPHONE
ORANGE
RED
The Shure Model 450 Series II is a high output dynamic mi-
crophone designed for paging and dispatching applications.
This extremely rugged microphone features an omnidirec-
tional pickup pattern and a frequency response tailored for
optimum speech intelligibility. It also includes an impedance
selection switch and a locking press-to-talk switch. The
press-to-talk switch can be converted to a monitor/transmit
switch with the Shure RK199S Split-Bar Conversion Kit.
WIRING DIAGRAM
FIGURE 1
Table 1. Typical Cable-to-Connector Wiring
INPUT TYPE
WIRE
COLOR
FUNCTION
XLR
1/4 IN.
CONNECTOR PHONE JACK
GREEN
WHITE
SHIELD
AUDIO
PIN 2
PIN 3
PIN 1
TIP
Features
UNBALANCED
AUDIO GROUND
CHASSIS GROUND
SLEEVE
SLEEVE
•
•
•
•
•
Dual impedance
Locking press-to-talk switch
R
GREEN
WHITE
SHIELD
AUDIO +
AUDIO –
PIN 2
PIN 3
PIN 1
TIP
Rugged ARMO-DUR base and case
BALANCED
RING
Adjustable height
CHASSIS GROUND
SLEEVE
Optional monitor/transmit switch conversion kit
PRESS-TO-TALK SWITCH OPERATION
NOTE: The RED and BLACK leads are not part of the audio
circuit. These wires provide a contact closure when the press-
to-talk switch is depressed. This closure may be used to con-
trol an external relay or a transmit/receive circuit.
To operate the control bar as a press–to–talk switch, simply
hold it down and begin speaking. When you are finished
speaking, release the control bar.
CHANGING PTT CIRCUIT TO NORMALLY OPEN
To lock the control bar in the “on” position, press it down and
pull it forward. To unlock the control bar, push it back and re-
lease it.
Using microphones in parallel requires a normally open mi-
crophone circuit. To modify the press–to–talk switch so that
it provides a normally open circuit, proceed as follows:
IMPEDANCE SELECTION
1. Remove the screws, washers, and bottom plate from
the microphone.
To select high or low impedance, move the impedance selec-
tion switch, located under the microphone base, to either the
HIGH or LO position. The switch is factory pre–set to LO.
2. Unsolder the black, red, and white leads from the terminal
of the press–to–talk switch (see Figure 1). Make
sure these leads are still soldered together. If necessary,
resolder them and insulate the connection.
Shure recommends the low impedance setting if long
lengths of cable are used, or if severe hum is encountered.
Use Shure A95 Line Matching Transformers to match a low
impedance (300 Ω) microphone line to a high impedance
amplifier input.
3. Replace the bottom plate and secure it with the screws
and washers removed in Step 1.
2005, Shure Incorporated
27C2917 (Rev. 3)
Printed in U.S.A.
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