YEONHWA M TECH MD Series User manual

User Manual
VHF Transceiver
MD-100D
UHF Transceiver
MD-400D

Version #1 (2017-08-01)
YeonHwa M Tech Co., Ltd.
36, Jeonparo 44beongil, Manangu, Anyangsi, Gyeonggido, Korea Tel: [phone]
MD-400D User Manual
1. MD-420D Digital RF Modem Specification
The MD-Series standardized the specifications of the instrument exterior and connectors so
that the digital RF modem can maintain compatibility with existing analog modems.
When using the digital mode, it is very efficient with the existing analog problems such as
data error, clean sound quality and volume, call distance, usage time
MD-Series Specification is as follows:
▪Usage frequency VHF : 136~174MHz, UHF : 400~470MHz
▪1 Zones 32 channels selectable (1zone = Max 32 channels)
▪Total 32 channels can be configured
▪5/1 Watt RF Power
▪Encryption is available as option (AES128, 256)
▪5 level S.Q selectable (Supports Analog).
▪Remote Radio Stun / Kill / Revive
▪Available to connect speaker of 1Watt
▪Data rate in wireless section : 9,600bps
▪RS-232C communication rate : Standard 115,200bps(Change available according to
program
setting)
▪Add AT Command for user convenience
▪User friendly for enabling PC based modem Control GUI Software
▪Aluminum metal Frame Body
▪Service connector : DE-15 pin Female Connector
▪Power supply : DC +9.0~DC+24V

2. Specification
2.1 MD-Series Specification
General
Frequency Range
Frequency Stability
Programmable Channels
Channel Spacing
Digital Vocoder
Dimensions
Weight
Power
Source
Current Drain (maximum)
MD
-100D : 136~174 MHz
MD
-400D : 400 ~470 MHz
±1.5ppm (
-30 to +60℃)
1 Zones / 32 Channels
12.5KHz
AMBE++
103mm(H) x 52mm(W) x 32mm(D)
280g
DC +9.0 ~ +24V
Receive mode, rated audio out
– 420 (Audio Max)
Transmit mode
– 1,200mA
Standby mode
– 110mA
Receiver
Sensitivity
Squelch Sensitivity
Selectivity
Spurious and Harmonic Rejection
FM Hum and Noise
Audio Output Power
Audio Distortion
Audio Response
Input Impedance
0.25uV 12 dB SINAD
0.22uV 10dB SINAD
65dB (12.5KHz)
75dB
40dB (12.5KHz)
1 Watt across an 16
-ohm load
Less than 3% at rated output
+1,
-3 dB from 6dB per octave de-emphasis
Characteristic from 300 ~ 3000Hz
50 ohms
Transmitter

RF Power Output
Spurious and Harmonic
FM Hum and Noise
Audio Distortion
Audio
Frequency Response
Output Impedance
5/1Watt
70dB
40dB (12.5KHz)
3% maximum with 1KHz modulation
+1,
-3dB from 6dB per octave pre-emphasis
Characteristic from 300 ~ 3000Hz
50ohms
3. MD Series Components
3.1 Equipment name
* Components may differ according to the request of buyers.
Figure 3-1) MD-400D Series Component

3.2 Status Display LED
This is LED which displays the equipment status.
The main status display is as follows:
①Red color when normal transmission
②Green color when normal receive
4. How to use MD-400D Series
4.1 Message transmission and receive tools
You can send and receive messages through the AT Command, but the PC tool is provided
to make it easier to use.

Figure 4-1) Message tool
4.1.1 Messages
It is possible to send and receive messages between the modem and the modem, and between
the modem and the terminal. By providing the PC interface as above, convenient configuration is
possible. You can configure the file or database connection to store additional messages.
Since it is based on PC, it can be saved as much as the capacity of the PC can be allocated, so it
can be seen that the capacity is not limited.
4.1.2 Basic Protocol
Supports an ACK message to determine whether the opponent terminal has received. When a
message is sent, the receiving terminal automatically sends an ACK message. When the message
is received, the other terminal informs the receiving terminal that the message has been received
normally.

Figure 4-2) Normal Message Transmission and Receive Method
Figure 4-3) Action on Message Transmission Error
If an error occurs in the delivery of the message, the specified number of retries will be retransmitted
after 5 seconds.
Finally, there is no format restriction of characters, and it supports messages of up to 80 characters.
4.1.3 AT Command
Use AT Command to set the status of the transceiver(radio) or to use the function.
After connecting the serial port, use the terminal program. The basic speed is 115,200 bps.
1) Modem version information verify command (VERSION)
Description
Command to verify the modem version information
Query
Answer
1. AT*VERSION
*VERSION:<value1>

Parameters <value1>
S/W Version
Example AT*VERSION
*VERSION:YEONHWA Modem v1.0
OK
2) Modem Status verify command (CHKSTAT)
Description
Command to verify modem status
Query
Answer
2. AT*CHKSTAT
*CHKSTAT:<value1>
Parameters <value1>
STAT OK – Normal status
STAT ERROR – Error status
Example AT*CHKSTAT
*CHKSTAT:STAT OK
OK
3) Modem information verify command (MINFO)
Description
Command to verify modem information
Query
Answer
3. AT*MINFO
*MINFO:<value1>,<value2>,<value3>,<value4>
Parameters <value1>
Channel number
<value2>
Frequency
<value3>
Call ID
<value4>
Group ID

Example AT*MINFO
*MINFO:1,440.000,1,1
OK
4) Modem Reset (RESET)
Description
Command to reset modem
Query
Answer AT*RESET
RESET
Parameters <value>
Reset the modem
Example AT*RESET
RESET
Going down terminal…
5) Sending Message (MSG)
Description
Command use when sending message
Query
Answer
AT*MSG=<value>
MSG OK
Parameters <value>
Message to be sent
Example AT*MSG=TEST
MSG OK
6) Receiving Message (RMSG)
Description

Command use when receiving message
Answer
RMSG=<value>
Parameters
<value>
Receive message
Example
RMSG=TEST
7) Check channel list (CHLIST?)
Description
Command to verify when receiving message
Answer
AT*CHLIST?
Parameters
CHNUM: <value> : Current channel number
Whole channel number: Classified channel number, RX
frequency, TX frequency
… <repeat>