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 12 3 LO HI BLACK RED GREEN BLACK WHITE SHURE MODEL 450 SERIES II SHIELD PAGING AND DISPATCHING MICROPHONE ORANGE The Shure Model 450 Series II is a high output dynamic mi- RED crophone designed for paging and dispatching applications. This extremely rugged microphone features an omnidirec- WIRING DIAGRAM tional pickup pattern and a frequency response tailored for FIGURE 1 optimum speech intelligibility. It also includes an impedance selection switch and a locking press-to-talk switch. The Table 1. Typical Cable-to-Connector Wiring press-to-talk switch can be converted to a monitor/transmit INPUT TYPE WIRE FUNCTION XLR 1/4 IN. switch with the Shure RK199S Split-Bar Conversion Kit. COLOR CONNECTOR PHONE JACK Features GREEN AUDIO PIN 2 TIP UNBALANCED WHITE AUDIO GROUND PIN 3 SLEEVE Dual impedance SHIELD CHASSIS GROUND PIN 1 SLEEVE Locking press-to-talk switch GREEN AUDIO + PIN 2 TIP Rugged ARMO-DUR base and case BALANCED WHITE AUDIO PIN 3 RING Adjustable height SHIELD CHASSIS GROUND PIN 1 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 operate the control bar as a presstotalk switch, simply to-talk switch is depressed. This closure may be used to con- hold it down and begin speaking. When you are finished trol an external relay or a transmit/receive circuit. speaking, release the control bar. To lock the control bar in the on position, press it down and CHANGING PTT CIRCUIT TO NORMALLY OPEN pull it forward. To unlock the control bar, push it back and re- Using microphones in parallel requires a normally open mi- lease it. crophone circuit. To modify the presstotalk switch so that it provides a normally open circuit, proceed as follows: IMPEDANCE SELECTION 1. Remove the screws, washers, and bottom plate from To select high or low impedance, move the impedance selec- the microphone. tion switch, located under the microphone base, to either the HIGH or LO position. The switch is factory preset to LO. 2. Unsolder the black, red, and white leads from terminals 2 and 3 of the presstotalk switch (see Figure 1). Make Shure recommends the low impedance setting if long sure these leads are still soldered together. If necessary, lengths of cable are used, or if severe hum is encountered. resolder them and insulate the connection. Use Shure A95 Line Matching Transformers to match a low impedance (300 ) microphone line to a high impedance 3. Replace the bottom plate and secure it with the screws amplifier input. and washers removed in Step 1. 2001, Shure Incorporated Printed in Mexico 27B2917 (AC) GREEN WHITETRANSMIT/MONITOR SWITCH CONVERSION KIT Cable 2.1 m (7 ft.) four-conductor, two conductors shielded, When the optional split-bar Transmit/Monitor Switch Conver- non-detachable sion Kit is installed, the Monitor bar must be depressed before the Transmit switch can be depressed, requiring the operator Case to verify that the channel is open before transmitting. The Two-tone gray ARMO-DUR Monitor bar can be locked in the on position. The Transmit bar is momentary and cannot be locked. NOTE: Transceiver wiring information must be obtained from the transceiver schematic and/or the manufacturer. SPECIFICATIONS Type Dynamic Frequency Response 200 to 5,000 Hz (see Figure 2) OVERALL DIMENSIONS FIGURE 3 Net Weight 737 grams (1 lb., 10 oz.) TYPICAL FREQUENCY RESPONSE Shipping Weight FIGURE 2 1020 grams (2 lb., 4 oz.) Polar Pattern Certification Omnidirectional Conforms to European Union directives, eligible to bear CE marking meets European Union EMC Immunity Re- Impedance (at 1,000 Hz) High Impedance: 30,000 quirements (EN 500821, 1992). Low Impedance: 225 REPLACEMENT PARTS Recommended Load Impedance Cartridge . R96 High Impedance: 100,000 Cable . C31C Low Impedance: 1,000 On/Off Switch . RK141S Output Level (at 1,000 Hz, Open Circuit Voltage) OPTIONAL ACCESSORIES High Impedance Low Impedance Transmit/Monitor Split-Bar Switch Kit . RK199S 35.0 dBV/Pa* 57.0 dBV/Pa* (17.8 mV) (1.4 mV) *1 Pa = 94 dB SPL Switches Locking Press-to-Talk Switch: Activates microphone cir- cuit and an external relay or control circuit. The micro- phone circuit is normally shorted. Impedance Selection Switch: Double-pole, double-throw slide switch located in the base of the microphone. SHURE Incorporated Web Address: