LMD-E1 is a converter that changes serial(RS232/TTL) communication to Ethernet communication.
Specifications and usage instructions are as follows.
For other technical and order-related matters, please contact our customer center (82-2-2272-5038).

1. Specification of LMD-E1

2. Features

  • Advanced & reliable TCP communication
  • Serial data up to 1500 bytes can be transmitted without error
  • Easy configuration by opening the web page UI
  • Hardware/software factory reset possible
  • Strong double-sided tape on the back makes it easy to attach anywhere
  • Operating environment: -40 ~ 85℃, 5 ~ 95%RH
  • Power: DC 3.0 ~ 5.5V, 9mA low power

3. Application

  1. LMD-E1 converts serial communication to Ethernet communication and vice versa in industrial equipment such as “PLC, electronic LED displays, measuring equipment, bus information systems, monitoring system, factory automation system, industrial machinery, parking guidance systems, etc.”
  2. When using TCP client mode, a more advanced features can be set such as “keep alive interval, keep alive custome packet..”.      Example) Keep alive cycle: 60 seconds, packet “TCP Client OK”
  3. TTL communication uses a standard cable while RS232 communication uses a optional cable. But the setup method is the same.

4. Components

Components of LMD-E1 converter

LED1(red): Lights up when power is turned on
LED2(sky-blue): It blinks quickly when the power is turned on, blinks at 1 second intervals when the LAN cable is connected, and blinks quickly whenever data is received.

[Note 1] When the LMD-E1 is delivered, the cable wire pins (4 pcs) are not inserted into the connector (MOLEX 5264-4P). This is to enable customers to insert/use according to the connector pin map of the serial device.
[Note 2] The black module in the middle of the cable is the “TTL to RS232” convertor. Settings/usage are the same.
[NOte 3] If you short-circuit the two pins with a driver for about 6 seconds until the light blue LED blinks quickly, the settings will return to the factory default state as shown below.
           – Serial communication:   115,200bps, N, 8, 1(Stop bit)
           – Ethernet communication: TCP Server,, #5000,,

5. How to set LMD-E1

1. Connect LMD-E1 and the serial device with a 4-pin cable.
– Power supply shall be “DC 3 ~ 5V”.
– TX-RX cables are connected crosswise.
– The picture on the right shows connection with a TTL cable.
The RS232 cable has a TTL to RS232 converter attached in the middle. The setting method is the same.



2. Connect LMD-E1 and your laptop with a RJ45 cable.

3. Manually set the laptop’s IP as follows (Windows 11 basis). 

3.1 Go to “Control Panel > Network and Internet > Network and Sharing Center > Change adapter settings“ to open the “Network Connections” window.

3.2 Right-click on any unused network cards (e.g. “Wi-Fi”) and change them to “Disable” (recommended).

3.3 Right-click on “Ethernet” and click “Properties > Internet Protocol Version 4 (TCP/IPv4) > Properties”.
Then, the “Properties” setting window appears.

3.4 Select “Use the following IP address” and set the IP of the laptop as below example.
– IP  address: (Example)
– Subnet mask:

3.6 Click “OK”.


4. Enter LMD-E1’s initial IP “” in the web browser.
And when the login webpage opens, set “Username, Password” to “admin” and click the “Login” button.




5. When the webpage below opens, set in the following steps:

Setting webpage of LMD-E1 converter

5.1 Change the Network parameter to the value you want.      Ex.) Refer to “Attachment 1/2, Setting Example”

5.2 Change the serial parameter to the desired value.               Ex.) 115200 > 9600 BPS

5.3 lick “Submit”. Then, the set value is applied to the LMD-E1 module.

[Tip 1] If you click “Reboot”, the converter CPU will be reset.
[Tip 2] If you click “FactoryReset”, all settings will be reset to factory default.
[Tip 3] If you click “Submit” after changing “Username, Password”, it will apply to the converter.
[Tip 4] If you change “Work mode” to “TCP client”, an advanced setting window will open where you can set more parameter. For details, refer to “Attachment 2”

Setting example of LMD-E1

[Note 4] When setting LMD-E1 to client mode, Local Port is fixed to “0”.
[Note 5] Set the target IP and port on the server side.
[Note 6] Network keepalive can be set on the server to check the client’s connection status. If the default value (cycle “0”) is maintained, it is inactive.
Here, the setting (example) is to send the “Client OK” packet (content) to the server every 60 seconds (cycle).