LM540 - Long Range Bluetooth 2.1+EDR USB Adapter

The LM540 - Long Range Bluetooth 2.1 + EDR USB Adapter is a qualified against the Bluetooth BT2.1 + EDR Standard and is available with or without support for the IVT Bluetooth software stack for use with a Windows PC or 'Other O/S' device respectively.

Long Range Bluetooth Adapter LM540 has a range of 800m when connected with a 2dbi Antenna

To confirm and prove the real-world performance of the adapter, LM Technologies tested the LM540 - Long Range Bluetooth USB Adapter at the Eaton Dorney Olympic Rowing club, as it offered a 2km flat open-space in which to conduct accurate testing. As the site had been used as a part of the 2012 Olympics it continues to feature Olympic-class distance markers laid-out every 100m.

By connecting two LM540 - Long Range Bluetooth USB Adapter's LM performed tests on device discovery (device searching), device pairing along with connection and re-connection, for each of the 100m distance markers. An additional GPS reading was taken from each of the locations where a connection was dropped and a reconnection was not possible.

The environment on the test day was favourable; clear (somewhat murky) with good visibility and low-winds, aiding in the achievement of the distances recorded. Bluetooth is extremely environmentally sensitive and therefore though LM was additionally able to replicate its results on a separate test date, weather conditions that offer a less helpful environment would make it highly unlikely to achieve the full distance obtained in tests performed on 'ideal' days.

In an effort to best guide and advise customers, LM Technologies provides a rough link-budget calculator that helps in promoting an understanding of the affect various obstacles may have on a wireless signal. Please note that this calculator is extremely rough and theoretical and should not be used as a real calculation of achievable distance; LM always recommends a real-world trial of wireless products to determine achievable distance and bit-rates: Wireless Link-Budget Calculator 

Brief Specification / Antenna Selection

The LM540 - Long Range Bluetooth 2.1 + EDR USB Adapter without antenna offers 15dbm output and therefore in-order to continue to comply within EU and US standard radio emissions requirements it is advised to chose an antenna with no more than a 5dBi rating. The LM540 - Long Range Bluetooth USB Adapter is packaged with a 2dBi antenna which should be sufficient for most applications.

The LM540 - Long Range Bluetooth USB Adapter supports both standard Windows and Linux BlueZ stacks, however LM also offers the adapter with the option of an Embedded IVT key, enabling support for the IVT Bluesoleil Bluetooth Stack, allowing for fast and simple connection to a Windows PC, along with support for the a range of profiles listed below:


When used with IVT Bluesoleil IVT v8.x Software.

To check that an adapter was purchased with IVT embedded key please see our Wiki:

Knowledge Base: LM540 IVT Bluesoleil License Problem

Long Range Bluetooth USB Adapter LM540 works as a plug-and-play device with Windows 98, XP, Vista, 7, 8, 8.1 and Linux when using Blue Z and Blue Z drivers.


  1. Bluetooth v2.1 + EDR compliant backward compatible with Bluetooth v2.0 + EDR/v1.2/v1.1 specification
  2. Bluetooth Class 1 Radio giving a range of up to 1000m depending on the selection of antenna
  3. 2-9 Dbi Antennas available which can increase the range to upto 1000 m
  4. Upto 3 Mbps data rate
  5. Transfer document, pictures, ring tones to and from your mobile, laptop, PDA and PC
  6. Small size 50.00mm (L) x 27.00mm (W) x 18.5mm (H)
  7. Easy, fast and intuitive setup and usage
  8. Supported by default Windows and Linux Bluetooth Drivers. IVT Bluesoleil also provided
  9. Supports upto 7 ACL link and 3 SCO links
  10. Lead free RoHS compliant
  11. Interoperability with PDAs & Phones


  1. Ideal solution for bluetooth proximity marketing
  2. High range achievable with a range of high gain antennas
  3. Robust Design
  4. Wide Range of Bluetooth Profiles available
  5. Support for audio profiles which means one can attend VoIP calls or listen to music via bluetooth
  6. Support for encryption data and authentication
  7. Adaptive Frequency hopping allows Co Existence with Wireless LAN without any interference
  8. Interoperable with PDAs, Phones

Product Variants

Part NumberDescription
540-0542BT2.1 Class 1 USB Adapter v2 CSR Adapter Only
540-0543BT2.1 Class 1 USB Adapter v2 CSR + 2dBi RP SMA Male Antenna
540-0545BT2.1 Class 1 USB Adapter Pack + 2Dbi Antenna
540-0546BT2.1 Class 1 USB Adapter IVT v8.x Software Retail Pack + 2Dbi Antenna

Product Specifications

LM540 – Long Range Bluetooth 2.1+EDR USB Adapter
ManufacturerLM Technologies Ltd
ChipsetCSR Bluecore 4 (BC04) ROM
Power ClassificationClass 1
Adapter TypeUSB Adapter
InterfaceUSB 2.0
Bluetooth SpecificationCore v2.1 + EDR backward compatible with Bluetooth v2.0+EDR/1.2/1.1 specification
Frequency2402 – 2480 MHz
Temperature Range-40 to +85 °C
Data Transfer RatesUpto 3 Mbps
Range100 – 1000 m
Tx Power17 dBm
Rx Sensitivity-86 dBm typical
Default FirmwareCSR HCI mode firmware
SoftwareMicrosoft Bluetooth Driver for Windowns XP/VISTA/7/8/8.1, IVT Bluesoleil for Windows, BlueZ for Linux
Size56 mm x 28 mm x 14 mm
Weight9 g
RoHS CompliantYes
OS SupportWin XP/VISTA/7/8/8.1, Linux
CertificationsFCC, RTTE

Related Products


CertificationLM540 CE RTTE Certificate
LM540 FCC Part 15B Certificate
LM540 FCC Part 15C Certificate
DatasheetLM540 Datasheet
DriversLM540 Bluesoleil 8.0 Driver (legacy)
LM540 Bluesoleil 10.0 Driver
Quick Start GuideLM540 QSG for Bluesoleil 8