Nikon CM200 service manual Microphone Connector Pin Function, Sci/Dtmf

6-6 ACCESSORIES & CONNECTOR PIN FUNCTIONS

3.0Microphone Connector Pin Function

Pin	Function	Description
1	9.3V	Regulated 9.3V Supply (50mA max.)
2	Boot/DTMF	This pin function depends on the voltage applied to pin 3 (See pin 3, Hook
	Keypad Column	description).
		When configured as “Boot”, applying 5V to this pin will set the radio to Boot
		state.
		When configured as “DTMF Keypad Column”, this pin will carry column
		voltages generated by the DTMF microphone (RMN5029).
3	Hook	When 0V is applied to this pin (mic on hook), pins 2 and 7 will be
		configured to “Column” and “Row”.
		When no voltage is applied to this pin (mic off hook), this pin will read 2.7V,
		and pins 2 and 7 will be configured to “Column” and “Row”.
		When 9.3V is applied to this pin (programming cables or Mag One mic
		RMN5018), pins 2 and 7 will be configured to “Boot” and “SCI”.
4	Ground	Used as ground
5	Mic. Audio	Audio input impedance: 500 ohms
	THIS	80 mV rms input (standard mic) or 1.8 mV rms (low cost mic) at 1 kHz for
		60% deviation.
		PAGE INTENTIONALLY LEFT BLANK
		This path is enabled when Mic. PTT (pin 6) is keyed
6	Mic. PTT	Microphone PTT is active low, so this port reads “0” when PTT is pressed
		and “1” when PTT is released.
		10 K ohms internal pull up resistor to 9.3 V.
		Pulling low this pin will also pull low, via a diode, pin 3 (external MIC PTT)
		of the accessory connector.
7	SCI/DTMF	The function of this pin depends on the voltage applied to pin 3 (see pin 3
	Keypad Row	description).
		When configured as “SCI”, serial communication with the radio is
		facilitated.
		When configured as “DTMF Keypad Row” this pin will carry new voltages
		generated by the DTMF mic (RMN5029)
8	Handset Rx	Handset audio output provides de-emphasized, muted Rx audio. The
	Audio	source impedance is 10 ohms and the output level (open circuit) is
		controlled by the volume control setting.