Connectors

This page provides detailed pinouts for all RS-UV3A connectors.

SMA Antenna Jack (ANT)

Parameter	Specification
Connector	SMA female
Impedance	50Ω
Max RF Input	-10 dBm
Max DC	25V

The antenna jack is shared between TX and RX via an internal RF switch.

DC Power Jack (VIN)

Parameter	Specification
Connector	5.5×2.1 mm barrel
Polarity	Center positive
Voltage	3.5V – 16V DC
Protection	Reverse polarity diode

Micro USB

Function	Description
Power	5V from USB host
Data	USB serial via FTDI FT230X
Default Baud	19200

Provides both power and serial communication through a single cable.

Arduino Header (JP1)

6-pin 0.1” header for microcontroller integration:

Pin	Signal	Direction	Description
1	DIN	Input	Digital input (PTT/SQ via AI command)
2	RXD	Input	Serial data to RS-UV3A
3	DOUT	Output	Digital output (configurable via AO command)
4	TXD	Output	Serial data from RS-UV3A
5	3.3V	Power	3.3V output for accessories
6	GND	Ground	Ground

DIN Functions (AI command)

Value	Function
0	Disabled
1	Squelch open input
2	PTT input (ground to TX)

DOUT Functions (AO command)

Value	Function
0	Always LOW
1	HIGH when squelch open
2	HIGH when DTMF detected
3	HIGH when transmitting
4	HIGH when CTCSS detected
5	Always HIGH
6	HIGH when VOX triggered

Logic Levels

• Input: 3.3V and 5V tolerant
• Output: 2V–5V (determined by VIO voltage)

I/O Connector (DE-9)

DE-9 male connector for external audio, serial, and control:

Pin	Signal	Direction	Description
1	TX Audio	Input	Line-level TX audio (adj. via VR3)
2	PTT	Input	Ground to transmit (-24V to +24V tolerant)
3	GND	Ground	Ground
4	RX Audio	Output	Line-level RX audio (adj. via VU command)
5	COR	Output	Open-drain, LOW when squelch open
6	PWR	Power	8.5V if I/O_P jumper installed
7	E_TX	I/O	Serial TXD or TX indicator (see EX command)
8	E_RX	I/O	Serial RXD or SQ indicator (see EX command)
9	GND	Ground	Ground

TTL Levels Only!

This is NOT a standard RS-232 connector. It uses 3.3V/5V TTL logic levels. Connecting to RS-232 equipment may damage the RS-UV3A.

COR Output Specifications

Parameter	Specification
Type	Open-drain, active LOW
Current	150 mA max
Voltage	12V max

E_TX/E_RX Functions (EX command)

Mode	E_TX (pin 7)	E_RX (pin 8)
0	HIGH when TX	LOW when SQ open
1	Serial TXD	Serial RXD

Speaker/Mic Jack (SPK/MIC)

4-conductor 3.5mm TRRS jack for speaker-microphone:

Contact	Signal	Description
Tip	Speaker +	Speaker audio output
Ring 1	Microphone	Mic input (3.3V bias)
Ring 2	PTT	Ground to transmit
Sleeve	Ground	Common ground

Compatible with standard speaker-microphones wired in this configuration.

Internal Audio/PTT

Direct solder pads for enclosure-mounted components:

Pad	Signal	Description
SPKR	Speaker out	8Ω speaker, level via VR1
MIC	Microphone in	3.3V bias for electret
PTT	Push-to-talk	Ground to transmit

Ground pads are located adjacent to each signal pad.

Microphone Bias

The MIC input provides 3.3V bias through R6 for electret microphone elements. For dynamic microphones or external preamps:

• Remove R6 and relocate to R7 position, OR
• Add a DC blocking capacitor in series

USB Serial Header (JP2)

6-pin header for FTDI cable or direct connection:

Pin	Signal	Description
1	GND	Ground
2	CTS	Clear to send (optional)
3	VIO	Reference voltage for logic levels
4	TXD	Serial out from RS-UV3A
5	RXD	Serial in to RS-UV3A
6	RTS	Request to send (optional)

Note

JP1 and JP2 share the same serial port. Use only one at a time.

Amplifier Header (AMP)

6-pin header for RS-UVPA power amplifier connection:

Pin	Signal	Description
1	RC1	Digital control output 1
2	RC2	Digital control output 2
3	AN1	Analog input 1
4	AN2	Analog input 2
5	+8.5V	Power output
6	GND	Ground

Power Switch Header (PW)

2-pin header for external power switch:

Pin	Signal
1	VIN+
2	VIN+ (through jumper)

• Ships with jumper installed (power always on)
• Remove jumper and wire to SPST switch for on/off control
• Can be used as alternate power input

PA Header and SJ1

Internal RF connection point for RS-UVPA integration:

Component	Description
PA Header	RF in/out for internal amplifier
SJ1	Solder jumper (factory-installed)

• SJ1 closed (default): RF routes to ANT jack
• SJ1 open: RF routes to PA header for amplifier connection

To install RS-UVPA: Clear solder from SJ1, connect amp to PA header.

ICSP Header

In-circuit serial programming header for PIC18F45K22:

    1   2
    ●   ●
    3   4
    ●   ●
    5   6
    ●   ●

Pins are staggered to allow programming without soldering a header.

Bootloader Jumper Positions

Jumper	Result
1-2	Boot to bootloader on USB/JP1 serial
4-5	Boot to bootloader on DE-9 serial

I/O Power Header (I/O_P)

2-pin jumper to enable 8.5V on DE-9 pin 6:

State	Result
Open	Pin 6 not connected
Jumpered	Pin 6 = 8.5V

Useful for powering external accessories like GPS modules.

26 MHz Output (26M)

Single-pin access to 26 MHz TCXO reference:

Parameter	Specification
Signal	26 MHz square wave
Purpose	Sub-receiver reference
Usage	Advanced applications only