Shure 450 Series II manual Wiring Connections, PRESS-TO-TALK Switch Operation

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

SHURE MODEL 450 SERIES II

PAGING AND DISPATCHING MICROPHONE

GREEN

LO

ORANGE

YELLOW

	HI
GREEN	WHITE

1 2 3

BLACK

BLACK

RED

GREEN

WHITE

SHIELD

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.

Features

•Dual impedance

•Locking press-to-talk switch

•Rugged ARMO-DURRbase and case

•Adjustable height

•Optional monitor/transmit switch conversion kit

PRESS-TO-TALK SWITCH OPERATION

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.

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.

IMPEDANCE SELECTION

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.

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.

RED

WIRING DIAGRAM

FIGURE 1

Table 1. Typical Cable-to-Connector Wiring

INPUT TYPE	WIRE	FUNCTION	XLR	1/4 IN.
	COLOR		CONNECTOR	PHONE JACK
	GREEN	AUDIO	PIN 2	TIP
UNBALANCED	WHITE	AUDIO GROUND	PIN 3	SLEEVE
	SHIELD	CHASSIS GROUND	PIN 1	SLEEVE
	GREEN	AUDIO +	PIN 2	TIP
BALANCED	WHITE	AUDIO –	PIN 3	RING
	SHIELD	CHASSIS GROUND	PIN 1	SLEEVE

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.

CHANGING PTT CIRCUIT TO NORMALLY OPEN

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:

1.Remove the screws, washers, and bottom plate from the microphone.

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.

3.Replace the bottom plate and secure it with the screws and washers removed in Step 1.

2005, Shure Incorporated	Printed in U.S.A.
27C2917 (Rev. 3)