Operation, Internal Connections, General

Model 577B User Guide

NOISE-CANCELING HANDHELD DYNAMIC MICROPHONE

OPERATION

For optimum performance and maximum rejection of background noise, place your upper lip against the lip guard, approximately 25 mm (1 in.) from the grille. Hold down the push-to-talk button while talking normally.

INTERNAL CONNECTIONS

The 577B is a balanced-line, low-impedance dynamic microphone. It is designed for direct connection to low-impedance microphone inputs and/or installations where long cable lengths are needed. It includes a four-conductor (two conductors shielded) coiled-cord cable and a double-pole, single-throw, leaf-type switch. The NATURAL and GREEN leads are the “hot” audio conductors; the shield is connected to microphone circuit ground. The RED and BLACK leads control the switch circuit. The microphone circuit is open when the switch is open, but can be easily modified for normally shorted operation. Refer to Figure 1.

GENERAL

The Shure Model 577B SONOBAR® Microphone is a handheld dynamic microphone designed for communications and paging applications that require highly intelligible, low noise output. It can be used in all types of mobile communications, from amateur radio to helicopter news and traffic reports. It is also suitable for public address and paging systems in noisy areas such as factories, airport terminals, and restaurants.

The 577B represents a significant improvement over most microphones with anti-noise features. Shaped frequency response, directionality, and distant sound discrimination contribute to total noise reduction. The microphone operates on the pressure-gradient principle and has two sound entry ports spaced a small distance apart.

The modular design of the 577B greatly facilitates field servicing. The cartridge, switch, and cable can be replaced in a matter of minutes, if necessary.

The 577B is built to withstand mechanical shocks, vibration, high

temperatures, and humidity. The exclusive ARMO-DUR®case is impervious to oil, grease, fumes, salt spray, sun, and corrosion. The “Million-Cycle” press-to-talk switch ensures years of reliable service.

A mounting bracket is supplied to provide convenient hang-up when the microphone is not in use.

Features

•Frequency response tailored for close-talk operation

•Extremely effective noise cancellation

•Dynamic microphone cartridge

•Modular design

•“Million-cycle” leaf-type press-to-talk switch

•TRIPLE-FLEX®cable provides three to four times the flex life of most coiled cords

•Rugged ARMO-DUR®case

•Built-in hang-up button and supplied mounting bracket

INTERNAL CONNECTIONS

FIGURE 1

TABLE 1. CABLE-TO-CONNECTOR WIRING

INPUT TYPE	WIRE	FUNCTION	XLR	1/4 INCH
	COLOR		CONNECT	PHONE
			OR	PLUG

	NATURAL	AUDIO +	PIN 2	TIP

BALANCED	GREEN	AUDIO –	PIN 3	RING

	SHIELD	CHASSIS	PIN 1	SLEEVE
		GROUND

	NATURAL	AUDIO	--	TIP

UNBALANCED	GREEN	AUDIO	--	SLEEVE
		GROUND

	SHIELD	CHASSIS	--	SLEEVE
		GROUND

Printed in U.S.A.