Philips SM30 manual Block diagram

				2-channel p.a. amplifier for
			SQ45 call and music applications
			music	call
			input					output
			1V					100/70/50V
					Pilot tone
				Line output module
Radio	1		Music input
Cassette	2
C D	3		module
			Recorded			1Zone relay 1				Loudspeaker
					Chime-,					zones 1-6
	message				attention-,		module
			module						6
	1	Call station 1			alarm-,	2	Zone relay		7	Loudspeaker
					signals
			input
	2						module			zones 7-12
			module					12
	3Microphone2					3		13
			input				Zone relay			Loudspeaker
	4		module				module	18
										zones 13-18
	5		Optional 3	Microprocessor					1
						Control relay				Relay
			input		board
	6						module		12	outputs 1-12
			module
	1
	Control input
	8		module
AC				Power
DC				supply	Displ/keyboard
					Sound Management
			SM30 System				4SM30011

Fig. 1 - Block diagram

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