Microphone Connector Pin Functions - Motorola Commercial Series Basic Service Manual

Microphone Connector Pin Function
3.0 Microphone Connector Pin Function
Pin Function
1 9.3V
2 Boot/DTMF
Keypad Column
3 Hook
4 Ground
5 Mic. Audio
6 Mic. PTT
7 SCI/DTMF
Keypad Row
8 Handset Rx
Audio
Regulated 9.3V Supply (50mA max.)
This pin function depends on the voltage applied to pin 3 (See pin 3, Hook
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).
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".
Used as ground
Audio input impedance: 500 ohms
80 mV rms input (standard mic) or 1.8 mV rms (low cost mic) at 1 kHz for
60% deviation.
This path is enabled when Mic. PTT (pin 6) is keyed
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.
The function of this pin depends on the voltage applied to pin 3 (see pin 3
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)
Handset audio output provides de-emphasized, muted Rx audio. The
source impedance is 10 ohms and the output level (open circuit) is
controlled by the volume control setting.
Description
6-5