Icom IC F110S, IC F111S, IC F121S service manual Switching circuit Main unit Q23

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Pin	Port	Description
number	name
		Outputs control signal for the power
41	PWON	switching circuit (MAIN unit; Q23,
		Q24).
42	NWC	Outputs IF bandwidth control signal.
		Low : While IF bandwidth is narrow.
		Outputs control signal for the AF mute
43	AFON	circuit (MAIN unit; Q35, Q36, D29).
		High : While AF amplifier (MAIN unit;
		IC8) is activated.
44–46	OPT3–	I/O ports for the optional board control
	OPT1	signals.
47	BUSY	Outputs BUSY detection signal for the
		optional board via MAIN unit, J1.
48	SI	Input port for the clock signal from the
		optional board via MAIN unit, J1.
49	CLI	Input port for the cloning signal.
50	CLO	Output port for the cloning signal.
51	POSW	Input for the POWER switch.
52	IGSW	Input port for the remort control signal
		from external connector (Main unit; J6).
53	NOIS	Input port for the “NOIS” signal which is
		used noise squelch operation from the
		FM IC (MAIN unit; IC1)
54	CIRQ	Input port for the interruption signal
		from the optional board via MAIN unit,
		J1.
55	CCS	Outputs the chip select signal for the
		optional board via MAIN unit, J1.
56	PTT	Input port for the PTT switch from
		microphone.
		Input port for the PTT switch from the
57	EPTT	external connector (MAIN unit; J6).
		Low : External PTT switch is ON.
		Input port for the microphone hanger
58	HANG	detection signal.
		Low :The microphone on hook.
		Input port for the AF volume control
59	AFVI	(FRONT unit; R14).
		High : [VOL] is maximum clockwise.
60	CDEC	Input port for CTCSS/DTCS decoding
		signals.
61	SDEC	Input port for the single tone decoding
		signals.
62	OPV1V2	Input port for the optional board detec-
		tion signal.
63	RSSI	Input port for the decoding signal of the
		received signal strength.
64	LVIN	Input port for the PLL lock voltage.

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