LM048: Changing the baud rate using the LM149 tool (Video)

The default firmware on the LM048 has a Baud-Rate of 19200.

In the video below our engineer demonstrates how to use our LM149 configuration tool to change the Baud-Rate on the LM048 and LM058.  When you change the Baud-Rate you have to select “Save Settings” to ensure that the tool sends the correct commands to the device and saves the configuration changes.

You can see that baud rates from 1200, 2400, 4800 to 9600 are supported and modified according to the response received from the AT+ENQ command. After you submit the AT+Reset command, the default baud rate of 19200 is loaded (the LM048/LM058 device will also be reset if you press and hold the Reset button continuously for 3 seconds).



LM048: Connecting to a Windows PC over Bluetooth (Video)


In the video below our engineer shows how to connect the LM048 adapter to a Windows PC over Bluetooth via dongle.

  • Make sure the DCE/DTE switch is towards DCE when LM048 is communicating with PC.
  • Reset the adapter with RESET switch pressed for 3 seconds.
  • After reset, observe the power on LED sequence – All LEDs blinks for 3 times. Then make sure the LED sequence is RED-ON, Yellow-OFF, Blue Blinking.
  • Try reading the settings from  LM048 with LM149 tool.
  • After you successfully pair PC with LM device, PC opens two comports(standard Serial Over Bluetooth Link). You need to check which comport is for outgoing connection (PC=master and LM-device=slave).
    Then open that comport on your PC, you should see the connection established and data transfer.



  • The TX-RX LEDs on external adapter glows only when LM149 is communicating for reading settings.
  • The Amber LED should never be on while issuing commands. The Blue LED should be blinking (not constantly ON).

LM048: Cannot open serial port

Ensure that all LM048 adapters have the same firmware version and configuration.

In it’s default configuration the LM048 is in slave mode, and the blue LED will blink approximately once per second. The blue LED will begin to blink faster when it receives a connection request, and enters into pairing mode.

If the pairing procedure is completed successfully and the connection to remote device is established. the blue LED will be steady. Check that the PIN of the LM048 is same as your remote device otherwise the connection will fail.

If your problem persists please contact support.

LM048: Modifying the connection supervision timeout

This parameter can be modified by a user if they have a AT command interface. The current firmware does not include AT commands to modify this parameter.

Firmware can be customised to user needs (depending on development time, cost and volume). If you’re interested in customised firmware, please contact the sales team here.

LM048: Sending RS232 data to Excel

It’s possible to read serial port data in Excel using an ActiveX control such as StrokeReader.

Another possible method would be to use the MSComm control that comes with Visual Basic.

Why am I experiencing a delay when sending messages?

After the LM048 connects to a remote device, the local host observes a delay (milliseconds) when receiving messages from the LM048 at particular data rates.

While the LM048 is connected to the remote device it enters into “Online-data-mode”. In “Online-data-mode”, if “AT+ESC+” setting is present the LM048 keeps on checking for an escape sequence from the local host. After receiving the escape sequence the LM048 terminates the “Online-data-mode”, followed by entering the Online-command-mode.

Using the “Online-command-mode”, you can change/query the LM048 settings or can issue the disconnect command to terminate it.

The escape sequence check algorithm may cause a delay in forwarding the messages if some specific timings for the data rate are matched.

If you do not need to initiate the connection-termination from the LM048 or you do not require the Online-command-mode or observed the above issue, then use the “AT+ESC-” setting on your device.
Note 1: The escape sequence checks it is applicable to all Bluetooth v2.0 and v2.1 firmware versions

Note 2: The default setting is “AT+ESC+”.


LM048: Remote Configuration via Serial Adapter

This article describes remote configuration of LM048/LM058 Adapter using another Bluetooth Serial Adapter which could be another LM048/LM058 adapter. For Setup procedure please look at the article LM048: Remote Configuration of Serial Adapter via Bluetooth Connection

Read more

LM048: Remote Configuration via USB Adapter or in-Built Bluetooth of PC

This article describes remote configuration of LM048/LM058 Adapter using a Bluetooth USB Adapter or in-built Bluetooth of PC/Laptop. For Setup procedure please look at the article LM048: Remote Configuration of Serial Adapter via Bluetooth Connection

Read more

LM048: Common Issues

Problem 1

I am able to connect to LM048/LM058 Serial Adapter, but no communication is happening?


I am able to connect to LM048/LM058 Serial Adapter, but communication data is garbled/garbage/incomprehensible? Read more

LM048: Modem/RS232 Signal Handling

This article explains how LM048/LM058 Serial Adapter handles the RS232 control signals also known as modem signals. This article also covers how to configure your LM048/LM058 Serial Adapter so that the modem signals can be transmitted to the remote end over Bluetooth. Read more

LM048: How to use with Bluetooth USB Adapter

This article explains how to use LM048 with a Bluetooth USB Adapter or in-built Bluetooth Controller of a lapotop/PC running Windows.

The below steps are shown using a Windows 7 Desktop machine with a Bluetooth USB Adapter and Hercules Setup Utility Serial Terminal.

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LM048: How do I pair two LM048s to auto-connect to each other?

A pair of LM048 or LM058 Adapters can be configured to auto-connect to each other when powered up. This procedure is calling Pairing up the adapters. This procedure is ideal when a pair of adapters are used as a serial cable replacement solution. For example a serial cable connection between a POS terminal and label printer can be replaced by a couple of LM048 Adapters paired with each other.

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LM048: How can I configure my Bluetooth Adapter?

Finding your firmware number

lm048_fw_locationFirst of all, you will need your Firmware Number, which you can find on the label on the back of your product, as pictured here.

This Firmware Number will identify which configuration software you need to use to configure the device.

Fw: v6.5 or higher requires LM149 Configuration Tool

Fw: v4.22 or lower requires LM049 Configuration Tool


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LM048: Remote Configuration of Serial Adapter via Bluetooth Connection


This document explains the procedure to configure LM Technologies Bluetooth Serial Adapters – LM048 and LM058, remotely via Bluetooth. Please note the adapter should be programmed with v6.54.MT firmware for this feature to work. This feature is not supported in the standard v6.54 firmware. Read more