LM740 Multimedia Legacy Firmware Notes

LM-SRX-ATC Firmware Release Notes

LM-SRX-ATC firmware offers AT Command interface to LM740 Multimedia Module. The firmware supports HFP, A2DP, AVRCP, PBAP and SPP profiles. For more details on the AT Command set, please read the Multimedia Firmware AT Command Manual.


  • Firmware upgrade procedure changed from USB to UART


  • Added separate command to create PBAP connection
  • Minor Bug Fixes


  • Name length issue fixed
  • Query Pincode issue fixed
  • LED and general settings minor bugs fixed
  • Deep Sleep timer issues fixed
  • Some connection issues fixed


  • PBAP Profile connection issue fixed
  • Firmware instability issues fixed
  • HFP Call waiting notification added
  • HFP Conference calling feature added
  • Deep sleep timer issue fixed
  • HFP Get operator name buffer size increased
  • A2DP playback commands return ERROR when HFP call is active
  • HFP/A2DP Query volume commands changed from AT+X or AT-X to AT+V? and AT-V? respectively
  • When there is no SIM in the phone, Get Operator name returns ERROR
  • Pairing records issue fixed
  • SPP Escape sequence issue fixed
  • A2DP volume issue fixed
  • PBAP profile issues fixed when phone has no SIM Card


  • PBAP Pull Phonebook feature implemented
  • Some firmware instabilities fixed
  • A2DP Streaming Start/Stop indication added
  • Some modifications made to LED behaviour
  • Minor SPP Profile bug fixes
  • SPP unidirectional data transfer issue fixed


  • LED changes updated
  • Firmware supported only on 16MB flash because of increase in firmware image size


  • Minor SPP Connection issues fixed


  • List of paired devices emptied on SPP disconnection – Fixed
  • Issues in connect to paired devices command AT*C fixed
  • Pairing timer issues fixed
  • Sending Reset command AT*R1 loses local name – Fixed
  • Outgoing connection issues corrected


  • When country code is appended to caller ID, firmware crashes – Fixed
  • LED state machine bugs fixed
  • Set name command unable to accept special characters &(£$ etc – Fixed
  • When HFP connection is disconnected from Phone side and pairing deleted, new connection from firmware fails – Fixed
  • HFP firmware instabilities and crash fixed
  • Specified number dialing with country code supported


  • HFP volume issues resolved. Volume can only be changed when HFP connection is active
  • Correct format of Specified Number dialling command AT+D
  • Read BD Address response corrected
  • Read RSSI Command implemented
  • Command to just reset the firmware and not restore factory settings implemented
  • LED indications added


  • SPP Disconnect indication message corrected
  • Connection fail indication added
  • Deep sleep command AT*G format corrected
  • Query response formats for all commands made uniform
  • Report packet formats made uniform in all cases
  • Handsfree commands return rnOKrnERRORrn in unconnected state – Fixed
  • Sending Escape Sequence +++ in SPP Connected state disconnects SPP connection – Fixed
  • Indication packet corrected when connection dropped from remote end
  • Behaviour of AT*P changed to just control discoverability behaviour of the module. Earlier it was used to control the connectable behaviour of the module as well. Firmware is connectable at all times now
  • AT*R added to reset firmware and restore factory settings
  • AT*Y command added to get operator name in HFP connected state


  • ERROR response changed from ERR to ERROR
  • DFU upgrade command added to upgrade over USB
  • Incoming and Outgoing call indication included
  • Response for Escape Sequence added
  • Uniform format implemented for Report messages


  • Boot up message changed


  • Firmware downsized to fit in 8MB flash
  • Some minor bug fixes


  • First Version of firmware supporting HFP, A2DP, AVRCP profile