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Cable Eliminator








Bluetooth to Serial Adapter
 Installation and Configuration!

 The Bluetooth RS-232 Serial Adapter (LM048) eliminates the use of a RS232 serial cable, providing an easy-to-use, wireless connection with freedom of movement. This adaptor allows any device with a standard 9-pin serial port to communicate wirelessly. In this setup guide we will go through the configuration and connection of two adapters connected to a computer and a printer.
  1. Plug the power supply into the adapter
  2. Adjust the slide switch depending on whether the device is a DTE (terminal) or a DCE (computer). If the device normally uses a straight through cable to connect to the computer then both devices should be set to DCE. If the device normally uses a null modem cable (where transmit and received are crossed) then set one adapter as DCE and one as DTE.
  3. Plug the adapter into the serial port. The indicator lights on the adapter should light
  4. Configure the adapter, if necessary. You can configure the adapter using the included Windows configuration utility, or by configuring the adapter directly by using a terminal program, such as Hyperterm

Configuring the Bluetooth adapter with Windows configuration utility

1. Insert the CD-ROM, the welcome screen should appear

2. Press the 'Install' button.

3. Select the COM port you are using to connect your adapter

4. Connect the adapter to the COM port of your PC
5. Power with the adapter with the power supply provided (you can power the adapter using the provided USB cable)
6. press the 'Get Adapter' button to get the current settings from the adapter.


  • The adapter should not be actively paired with another when getting settings. You must first disconnect the pair before getting settings.

  • The slide switch should be in the DCE (towards the LM logo) when communicating with the computer.


The status window shows current progress in connecting to the device. As the device steps through all the possible setting options looking for a match reading the configuration may take some time. The 'debug' option will show communication details about the session.


The device will respond "Device Programmed" after the programming is complete.

Tip: The Windows configurator for the Bluetooth adapter is a actually an automated method of sending AT commands to the adapter. If quick setup or precise control is an issue, then use the direct serial control method, described below.

Pairing Adapters

Pairing adapters lets you use two adapters to wireless connect a serial device. In this mode the adapters serve as a serial cable eliminator. In a pared mode one adapter functions as a 'master' and the other as a 'slave'.


  • Use the same serial port settings (baud rate, parity, etc) for the adapters as the device.

  • Once the adapters are paired, you must disconnect the pair before changing  settings. Do this by pressing the 'Disconnect' button in the configuration utility,, entering'+++' via direct serial connection, or by briefly pressing the reset button on the device.

Using Bluetooth adapter as a cable eliminator

Determine the baud rate of the current connection. change the settings on both devices if necessary. Also set the handshaking stop bits if necessary. (Star Sync users should turn off adapter handshaking). If the device happens to use the default values (19200 baud, 8,1,none etc) then no change is necessary. If setting changes are required then run the configuration on both adapters using the default settings.

After pairing configuration:

  1. Place the master device on the computer end, slide the switch towards the connector.

  2. Place the slave end on the device and slide the switch away from the connector.

  3. The device should now be connected. You can confirm data is flowing by checking the data indicator (middle yellow) light on the adapter.


Configuring the adapter via direct serial connection

The adapter will respond to commands sent to it over the serial connection. It uses an extension of the AT command set, also used by modems. To configure the adapter using a direct serial connection open a terminal program, such as Hyperterm and select the serial port used to connect to the adapter.

Terminal Settings

  • Bits per second: 19200 bps (baud rate)
  • Data bit: 8
  • Parity: None
  • Stop bit: 1
  • Flow control: H/W

Master Role Configuration

You can use "ATR0" to change the adaptor to the master role.  "ATR1" sets adapter to slave role.

When the adaptor is in the master role, you can use "ATO1" to manually set up a connection and "ATF?" to find the device you want to connect.

AT Command Set

The following is the AT command set for the local adaptor in the command mode (that is, the local adaptor is in the disconnection state).

All the commands and parameters are case insensitive.  "ATI1" shows the current settings of the adapter.

Please note; ATF ; This command is available only when the adaptor is in the manual master role. In other words, you should send "ATR0", "ATO1" before sending "ATF command "



+++ Escape. When the device is in Data (or paired) mode, it can be forced back into Command mode while maintaining the connection to the remote device. The sequence characters should be with 1000ms guard time.


Auto Connect. This command is used to enable/disable auto-connection feature in master role. By the way, it is used to online switch from command mode to data mode.

Note, it will cause a reboot when ATO0 or ATO1 take effect.


Online switch from Command mode to Data mode. You should see a 'Connect <device ID> after the devices connect.


Automatically connect the adaptor to a device specified by "ATD=xxxxxxxxxxxx " or any available device if "ATD= " is not assigned.


Disable auto-connection feature. After it is executed, you need to execute "ATA" to manually connect a remote device.


Inquire the current setting.


This command is used to establish a connection.

It is available only when the adaptor is in the manual master role.


Connect the adaptor to a specified Bluetooth device. It is available only when "ATD=xxxxxxxxxxxx" is executed.


Connect the adaptor to a device in the neighborhood found through "ATF?"



Inquire the Bluetooth address of the local adaptor.


Handshaking. This command enable or disable flow control signals (CTS/RTS) of the UART port.
 Note, the setting
 is not affected by ATZ0 but will cause a reboot


Disable flow control.


Enable flow control.


Inquire the current setting


For security purpose, this command is used to specify a unique remote Bluetooth serial adaptor to be connected. In the master role, the adaptor pairs and connects with the designated remote slave address. In the slave mode, this command is a filter condition to accept the inquiry of the master device.


"xxxxxxxxxxxx" is a string of 12 hexadecimal digits.


Restore the status in which the adaptor can connect with any remote address.


Inquiry the designated address that can be paired and connected.


Echo. This command is used to specify whether the adaptor echoes characters received from the UART back to the Host in command mode.


Characters received from the UART will not echo back to the Host.


Characters received from the UART will echo back to the Host.


Inquire the current setting.




Find. This command is used to search for any Bluetooth device in the neighborhood within one minute. If any device is found, its name and address will be listed. The search ends with a message "Inquiry ends. xx device(s) found."

This command is available only when the adaptor is in the manual master role.


Inquire Bluetooth devices in the neighborhood, listing 8 devices the maximum


Hang-up. This command is used to drop the connection either master or slave role. And it is used to specify whether the adaptor can be discovered by remote master devices. Note, it will cause a reboot when ATH0 or ATH1 take effect.


Drop current connection in Online Command mode.


The adaptor enters the undiscoverable mode. If a pair has been made, the original connection can be resumed. But other remote master device cannot discover this adaptor.

H  (default)

The adaptor enters the discoverable mode.


Inquire the current setting.


Information - current Settings. This command is used to inquire for information about the adapter.

I 0

Inquire the version codes.

I 1

List all current setting value.

I 2

Inquire RSSI in Online Command mode.


Stop bits. This command is used to specify one or two stop bits of COM port.


One stop bit.


Two stop bits.


Inquire the current setting.


Baud Rate. This command is used to specify the baud rate of COM port.


1200 bps


2400 bps


4800 bps


9600 bps
L2  (default)

19200 bps


38400 bps


57600 bps


115200 bps


230.4 Kbps


Inquire the current baud rate.


Parity. This command is used to specify parity bit setting of COM port.


None parity bit.


Odd parity.


Eve Even parity


Inquire the current setting




Name. This command is used to specify a name for the adaptor.

You can specify a friendly name using 0 to 9, A to Z, a to z, space and –, which are all valid characters. Note that "first space or -, last space or – isn’t permitted". The default name is "Serial Adaptor".


"xxxxxx" is a character string with a maximal length of 16.


Inquire the name of the local adaptor.
P PIN. This command is used to specify a PIN. The default PIN is "1234". Paired adaptors should have a same PIN.


"xxxx" is a 4~8-digit string.


Cancel authentication by PIN.


Inquire the current PIN.
Q Result Codes. The command is used to decide whether result messages are prompted when AT commands are executed. The result messages are: OK/ERROR for command execution, or CONNECT/DISCONNECT for connection status.


Prompt result messages.


Not prompt result messages.


Inquire the current setting.


Master/Slave mode. This command is used to specify whether the adaptor is in the master or slave role. If the device role is changed, the adaptor will reboot and all paired records will be cleared.


Set the adaptor to the master role.


Set the adaptor to the slave role.


Inquire the current role of the adaptor.
S Power  Save. This command is used to enable/disable auto-power saving feature of RS232 driver


Disable RS232 force on (auto power down)


Enable RS232 force on.


Inquire the current setting.
X Enable Escape. Disable/Enable escape sequence "+++".


Disable escape character check.


Enable escape character check


I Inquire the current setting.
Z Restore Defaults. This command is used to restore the default settings and reboot.


Restore the default settings.


  • 'ATO' connects to the two adapters after configuration.
  • Adapters must be paired before they will communicate. Use 'ATO1' to manually prepare the master and 'ATF?' to find the slave and  'ATD=<addr>' where <addr> is the 12 digit address chosen from the ATF list, and then 'ATA' to set up communication between master and slave..
  • The white slide switch on the adapter should be in the DCE position (towards the LM logo) to communicate with the computer in order to issue commands.


Can't connect to adapter.

1) check adapter is receiving power - the red and blue indicator lights should be lit when powered.

2) check that the data light (yellow) is occasionally flashing. If not check that the slide switch is in the correct position. Generally when talking with the computer, the slide should be in the DCE position (slide towards the LM logo)

3) You can disconnect and reconnect a wireless connection my pressing the reset button for a short press. The reset button accessed through small hole next to indicator lights. You can reset the adapter to factory defaults by pressing the reset button for 10 seconds.

Can't connect to serial device

1) Check the baud rate and other port settings. Port settings on the adapter(s) should match the device.

2) Handshaking controls access to serial ports. Make sure that the handshaking settings on the adapter matches the device.

3) If using 2 adapters in a master/slave arrangement, check to see that the adapters have been properly paired. The blue indicator light on the adapter is solid when paired, it flashes when unpaired.

Technical Support

If you are having problems with the Bluetooth-to-Serial Adapter that this page or our FAQ page does not address, please contact your reseller.

For More Information

Bluetooth to serial adapter

Adapter FAQ

USB to Serial Adapter

Ethernet to Serial Adapters:
    Digi One SP
    Moxa Nport 5110


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Copyright © 2009 Beagle Software. All rights reserved
Last reviewed January 06, 2009