Adjusting Signal Levels (Hardware) - ZUM Radio MMDVM-Pi User Manual

Elite 3.5 LCD ZUMspot kit user guide
Here's an example radio's (FT-7900) pin connection via the mini DIN 6 connector on the rear of the
radio:
Pin number

Adjusting signal levels (hardware)

Here is a picture of the test points on the PCB that can be used to look at the RX and TX signal levels on
an oscilloscope. The signal on JP7 is the RX signal audio on the ADC input pin of the STM32 chip. JP6 has
the TX signal audio on the pin going to the radio.
Copyright 2019-2022 ZUM Radio, Inc
Signal name
3 RX audio
4 Signal ground
6 TX audio
7 PTT
Wire color Mini DIN 6 connector
White 9600 from radio
Yellow GND
Green Audio to radio
Blue PTT
4 Rev 1.0