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RS-UV3A

System Commands

TX – Transmit

Section titled “TX – Transmit”

Controls the transmitter.

Syntax

Section titled “Syntax”
TXn

Parameters

Section titled “Parameters”
ValueDescription
0Stop transmitting (return to RX)
1–5Transmit with n-minute timeout

Examples

Section titled “Examples”
TX1             # Transmit, 1 minute max
TX3             # Transmit, 3 minute max
TX0             # Stop transmitting

Notes

Section titled “Notes”
  • TX0 stops TX even if hardware PTT is held
  • Timeout overrides TO setting for this transmission only
  • If TX is off, radio is in RX mode

PW – TX Power

Section titled “PW – TX Power”

Sets the transmit power level.

Syntax

Section titled “Syntax”
PWn
PW?

Parameters

Section titled “Parameters”
ValuePower Level
0Low (~10 mW, 10 dBm)
1High (~200 mW, 23 dBm)

Default

Section titled “Default”

1 (High)

Examples

Section titled “Examples”
PW1             # High power
PW0             # Low power
PW?             # Query current setting

TO – Timeout

Section titled “TO – Timeout”

Sets the transmit timeout timer.

Syntax

Section titled “Syntax”
TOnnn
TO?

Parameters

Section titled “Parameters”
ParameterRangeDescription
nnn000–600Timeout in seconds
000Disable timeout

Default

Section titled “Default”

000 (disabled)

Examples

Section titled “Examples”
TO180           # 3 minute timeout
TO300           # 5 minute timeout
TO000           # No timeout
TO?             # Query current setting

Notes

Section titled “Notes”
  • All 3 digits required
  • When timeout occurs, sends TG message and unkeys
  • Protects against stuck PTT

TG – Timeout Message

Section titled “TG – Timeout Message”

Sets the CW message sent when TX times out.

Syntax

Section titled “Syntax”
TG<text>
TG?

Parameters

Section titled “Parameters”
ParameterDescription
<text>Message up to 7 characters

Default

Section titled “Default”

‘TO’

Examples

Section titled “Examples”
TGTIME          # Send "TIME" on timeout
TGTO            # Send "TO" (default)
TG?             # Query current message

HT – Hang Time

Section titled “HT – Hang Time”

Sets TX hang time for repeater applications.

Syntax

Section titled “Syntax”
HTnnnn
HT?

Parameters

Section titled “Parameters”
ParameterRangeDescription
nnnn0000–5000Hang time in milliseconds

Default

Section titled “Default”

0000 (no hang time)

Examples

Section titled “Examples”
HT1500          # 1.5 second hang time
HT2000          # 2 second hang time
HT0000          # No hang time
HT?             # Query current setting

Notes

Section titled “Notes”
  • All 4 digits required
  • TX stays keyed for specified time after PTT release
  • Used with courtesy beep in repeater applications

CO – COR Inhibit

Section titled “CO – COR Inhibit”

Sets the COR (Carrier Operated Relay) inhibit time.

Syntax

Section titled “Syntax”
COnnnn
CO?

Parameters

Section titled “Parameters”
ParameterRangeDescription
nnnn0000–9999Inhibit time in milliseconds

Default

Section titled “Default”

0000

Examples

Section titled “Examples”
CO0150          # 150 ms inhibit
CO0200          # 200 ms inhibit
CO?             # Query current setting

Notes

Section titled “Notes”
  • Prevents COR from going active briefly after TX ends
  • Avoids squelch noise triggering COR
  • Useful for packet and repeater applications

CB – Courtesy Beep

Section titled “CB – Courtesy Beep”

Sets the courtesy beep for repeater applications.

Syntax

Section titled “Syntax”
CBn
CB?

Parameters

Section titled “Parameters”
ValueBeep
0None
1Low tone
2High tone
3High/low
4Two tones

Default

Section titled “Default”

0 (none)

Examples

Section titled “Examples”
CB0             # No beep
CB2             # High tone beep
CB?             # Query current setting

Notes

Section titled “Notes”
  • Sounds after hang time expires
  • Signals repeater is ready for next transmission

VX – VOX

Section titled “VX – VOX”

Enables or disables voice-operated transmit.

Syntax

Section titled “Syntax”
VXn
VX?

Parameters

Section titled “Parameters”
ValueDescription
0VOX off
1VOX on

Default

Section titled “Default”

0 (off)

Examples

Section titled “Examples”
VX1             # Enable VOX
VX0             # Disable VOX
VX?             # Query current setting

Notes

Section titled “Notes”
  • Pressing PTT disables VOX
  • Do not use with speaker-mic (RX audio will trigger TX)
  • Sensitivity set by VL command

VL – VOX Level

Section titled “VL – VOX Level”

Sets VOX sensitivity.

Syntax

Section titled “Syntax”
VLn
VL?

Parameters

Section titled “Parameters”
ValueSensitivity
0High (most sensitive)
1Medium
2Low (least sensitive)

Default

Section titled “Default”

1 (Medium)

Examples

Section titled “Examples”
VL0             # High sensitivity
VL2             # Low sensitivity
VL?             # Query current setting

BW – Bandwidth

Section titled “BW – Bandwidth”

Sets the channel bandwidth.

Syntax

Section titled “Syntax”
BWn
BW?

Parameters

Section titled “Parameters”
ValueBandwidth
012.5 kHz (narrow)
125 kHz (wide)

Default

Section titled “Default”

1 (25 kHz)

Examples

Section titled “Examples”
BW1             # 25 kHz (standard)
BW0             # 12.5 kHz (narrow)
BW?             # Query current setting

Notes

Section titled “Notes”
  • Requires power cycle to take effect
  • Use narrow for crowded bands
  • Some repeaters require narrow bandwidth

PD – Power Down

Section titled “PD – Power Down”

Controls the transceiver chip power.

Syntax

Section titled “Syntax”
PDn
PD?

Parameters

Section titled “Parameters”
ValueDescription
0Chip powered down
1Chip powered on

Default

Section titled “Default”

1 (on)

Examples

Section titled “Examples”
PD0             # Power down (saves ~70 mA)
PD1             # Power up
PD?             # Query state

Notes

Section titled “Notes”
  • Reduces current by approximately 70 mA
  • Radio cannot TX/RX when powered down
  • Serial commands still work

B1 – Baud Rate 1

Section titled “B1 – Baud Rate 1”

Sets the baud rate for serial port 1 (USB/JP1/JP2).

Syntax

Section titled “Syntax”
B1n
B1?

Parameters

Section titled “Parameters”
ValueBaud Rate
01200
14800
29600
319200
438400
557600

Default

Section titled “Default”

3 (19200)

Examples

Section titled “Examples”
B13             # Set to 19200
B15             # Set to 57600
B1?             # Query current setting

Notes

Section titled “Notes”
  • Requires power cycle to take effect
  • Reconnect terminal at new baud rate after power cycle

B2 – Baud Rate 2

Section titled “B2 – Baud Rate 2”

Sets the baud rate for serial port 2 (DE-9 I/O connector).

Syntax

Section titled “Syntax”
B2n
B2?

Parameters

Section titled “Parameters”

Same as B1.

Default

Section titled “Default”

3 (19200)

Notes

Section titled “Notes”
  • Only applies when EX1 (serial mode)
  • Requires power cycle to take effect

FW – Firmware Version

Section titled “FW – Firmware Version”

Reports the current firmware version.

Syntax

Section titled “Syntax”
FW

Response

Section titled “Response”
FW: 2.4A

Notes

Section titled “Notes”
  • Query only, no parameters

BL – Bootloader

Section titled “BL – Bootloader”

Enters bootloader mode for firmware updates.

Syntax

Section titled “Syntax”
BL

Notes

Section titled “Notes”
  • RS-UV3A waits indefinitely for bootloader connection
  • Power cycle required to exit without updating
  • See Firmware Upgrade guide

SS – Signal Strength

Section titled “SS – Signal Strength”

Reads the current receiver signal strength.

Syntax

Section titled “Syntax”
SS

Response

Section titled “Response”
SS: -85

Value is in dBm.

SN – Noise Level

Section titled “SN – Noise Level”

Reads the current receiver noise level.

Syntax

Section titled “Syntax”
SN

Response

Section titled “Response”
SN: 1234

Notes

Section titled “Notes”
  • Lower values indicate cleaner signal
  • Raw value, not calibrated

VT – Voltage

Section titled “VT – Voltage”

Reads the operating voltage.

Syntax

Section titled “Syntax”
VT

Response

Section titled “Response”
VT: 8.5V

Notes

Section titled “Notes”
  • Reads the 8.5V internal rail
  • Useful for monitoring power status

TP – Temperature

Section titled “TP – Temperature”

Reads the PCB temperature.

Syntax

Section titled “Syntax”
TP

Response

Section titled “Response”
TP: 42

Temperature in °C.

Notes

Section titled “Notes”
  • PCB temperature, not ambient
  • Will be warmer during TX

BS – Battery Status

Section titled “BS – Battery Status”

Legacy command for battery charger status.

Syntax

Section titled “Syntax”
BS

Response

Section titled “Response”
BS: 0

or

BS: 1

Notes

Section titled “Notes”
  • RS-UV3A Rev A does not have battery charging
  • Included for compatibility with older RS-UV3 versions

RR – Register Read

Section titled “RR – Register Read”

Reads an RDA1846S transceiver chip register. Advanced use.

Syntax

Section titled “Syntax”
RRxx

Parameters

Section titled “Parameters”
ParameterDescription
xxRegister address in hex

Response

Section titled “Response”

Returns 16-bit hex value.

Notes

Section titled “Notes”
  • For advanced debugging only
  • Register documentation available online for RDA1846S

RS – Register Set

Section titled “RS – Register Set”

Sets an RDA1846S transceiver chip register. Advanced use.

Syntax

Section titled “Syntax”
RSxxyyyy

Parameters

Section titled “Parameters”
ParameterDescription
xxRegister address in hex
yyyy16-bit value in hex

Response

Section titled “Response”
OK

or no response if failed.

Notes

Section titled “Notes”
  • Can disrupt radio operation if used incorrectly
  • For advanced debugging only
  • Settings may not persist through power cycle