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

LM048/LM058 serial adapter can be configured using another LM048/LM058 Serial Adapter. It doesn’t matter which adapter initiates the connection. The Serial Adapter which is being configured should have remote configuration setting enabled.

Remote Login Authentication Disabled

When remote authentication is disabled, the handshake sequence 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0x0D is replied with 0xBB 0xAA. The user doesn’t need to input any password.

Remote Configuration Using Serial Terminal

User can also use Serial Terminal to configure one serial adapter from another serial adapter. The procedure is the same as in above section. The “Configuring Serial Adapter” initiates Bluetooth connection to the “Configured Serial Adapter” and then sends handshake sequence and configures the adapter once handshake sequence is complete.  The below steps are shown using Hercules Setup Utility Serial Terminal on a Windows 7 PC. For complete set of AT Commands, please refer LM048 AT Command Manual.

Please note, it doesn’t matter which adapter initiates connection in this case. It is only for illustrative purposes we have assumed the “Configuring Serial Adapter” will be master and “Configured Serial Adapter” will be slave as this is the most common case. The “Configured Serial Adapter” can be master as well and can initiate connection to the “Configuring Serial Adapter”. What is important is that the 2 serial adapters should be connected via Bluetooth.

1/ Make sure the End of Line (EOL) character setting is set to Carriage Return (CR) on the serial terminal


2/ Connect the “Configuring Serial Adapter” to serial port and open serial terminal at factory serial settings of serial adapter i.e. 19200 8 N 1, flow: none. Set the role to master and disable auto-connect


3/ Search for Bluetooth Devices and then initiate connection using AT+CONN command


4/ Once Bluetooth connection is successful, send the handshake sequence 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0x0D as Hex characters or via “Send File” feature depending on the Serial terminal feature. The handshake file can be downloaded from handshake


5/ Once the handshake sequence is processed the user will get a reply 0xBB 0xAA when authentication is disabled or 0xBB 0xBB when authentication is enabled


6/ When handshake sequence is complete, user can send AT Commands and get a response. The user can use AT Commands to read or change settings. Please refer the LM048 AT Command Manual for the list of all AT Commands. Please note user will not see echo of AT Commands sent to LM048 but only responses as shown in the screenshot below for command AT, AT+VER, AT+ENQ


To exit remote configuration, send AT+AUTO command. OK response will be received and the remote serial adapter will switch back to data mode. To disconnect the connection, please send escape sequence +++ and then AT+DROP command or just power off the “Configuring Serial Adapter”.


Remote Login Authentication Enabled

Remote Login authentication is enabled when user sets a remote login password using the AT+RLOGIN command. The RLOGIN password should be between 5-16 characters long and have atleast 1 digit. The remote login password can be set only using a serial terminal locally. The remote login password cannot be read or changed remotely over a Bluetooth connection.

For setting remote configuration authentication please see LM048: Remote Configuration of Serial Adapter via Bluetooth Connection

Most of the steps of remote configuration are same as described in the except there is an extra authentication step before the adapter switches to remote configuration mode.

When the handshake sequence 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0x0D is sent to remote adapter, it responds with 0xBB 0xBB instead of 0xBB 0xAA when authentication is disabled. Remote login authentication requests can be handled with LM149 Software v1.6 or above as well as serial terminal. Both these scenarios are described below. Please note the remote login password for below section is LMT1234

Handling Remote Login Authentication Using Serial Terminal

When remote authentication is enabled, the procedure for remote configuration is same as described in section Remote Configuration using Serial Terminal except there is an extra step for remote authentication. The handshake sequence 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0xAA 0x0D is replied with 0xBB 0xBB

The user has to supply password using command AT+RLOGIN. If password is correct, handshake sequence is complete and user gets OK response. If password is not correct, user getsERROR response and handshake sequence fails. Please note the AT+RLOGIN response from user is not echoed, so not visible in the serial terminal window. This is shown in the screenshot below.