DMR818 : 2W Walkie Talkie Module With DMR Technology

DMR818 is a 2W long distance Digital walkie talkie module, it comes with built-in high performance microcontroller, digital mobile radio IC and RF power amplifier. All parameters(CTCSS, CDCSS, SQ, Predefined channels etc.) can be easily modified with protocol. With external power supply, speaker, and audio amplifier, it is easy to become a professional digital walkie talkie. Simplified interface and Ultra small size make this module widely used in various applications and conveniently embedded into various handheld device.
Remark: there are two versions of this module: DMR818-NVOC & DMR818-AMBE.
DMR818 strictly uses lead-free process for production and testing, and meets RoHS and Reach standards.

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Parameters	Test condition	Min.		Typ.		Max		Unit
Voltage range		3.3		4.2		5.0		V
Operating Temperature		-20		25		60		℃
Frequency range	@UHF	400				470		MHz
	@VHF	134				174		MHz
	@350	320				400		MHz
Start time				100				ms
Uart baud rate				57600				bps
Current Consumption
Sleep current				< 1				uA
Rx current				50				mA
Tx current （high power）	@VCC=4.0V			800				mA
Tx current （low power）	@VCC=4.0V			400				mA
RF Parameters
Tx power（high power）	@VCC=4.0V			1.5				W
Tx power（low power）				500				mW
adjacent-channel power	@12.5K offset			-62				dBm
Mic input voltage				0.1		1.6		Vpp
Rx Parameters
Sensitivity			-124				dBm
Receiving BER(DMR modulation)	@ -121dBm		1				%
Audio output amplitude			1.6		3.0		V
Audio Output impedance			30				KOhm

Type	DMR walkie talkie
Output Power	2W

Features of Digital Walkie Talkie DMR818

UHF band frequency: 400~470 MHz
VHF band frequency: 134~174 MHz
350 band frequency: 320~400 MHz
Distance up to 5Km
Max power output to 2W, low power to 0.5W
High Sensitivity: -124dBm
Bit error rate down to 1% under -121dBm
Independent frequency for Tx and Rx.
9 adjustable volume
Analog Bandwidth: 12.5 / 25 KHz Digital Bandwidth:6.25KHz
Message transmission and reception
DMR(Digital Mobile Radio)/ Analog walkie talkie
Built-in EEPROM, data saved even powered off
1ppm TCXO crystal
51 CTCSS
166 CDCSS

Typical Application Circuit of Digital Walkie Talkie DMR818

Pins of Digital Walkie Talkie DMR818

Pin NO.	Pin name	Description
1	MIC_IN	Microphone or line in
2	UART-TX	Transmit
3	UART-RX	receive
4	SWCLK	Reserved
5	SWDIO	Reserved
6	ARM_RST	Reserved
7	ANT	connect 50 ohm antenna
8	GND	Ground
9	GND	Ground
10	GND	Ground
11	VCC	External and Positive supply 3.3~5V
12	EZP_CS	Reserved for program Burning
13	CS	High level for normal working, leave open or pull low to enter sleeping mode
14	PTT	Module Input, Transmitting/receiving control, pull low to force the module to enter TX state; pull high for Rx state
15	+3.3V	3.3V output，connect to 50mA
16	LINE_OUT	Audio output
17	T/R	Module Output, status of Transmitting/receiving, High for TX and low for Rx
18	SPKEN	Audio amplifier control
19	GND	Ground
20	GND	Ground

Mechanical Dimensions of Digital Walkie Talkie DMR818