There are normal Bluetooth dongles, and there is the RN-240. This is a fantastically easy to use device that simply plugs into your existing RS232 port with no USB driver. It has an on-board DIP switch which allows the pairing ID to be set without software. To top it all, the device can be powered from the RS232 port, or through an external power connector built into the dongle housing.

The FireFly serial adapter is the world's smallest, lightest, and most capable Class 2 Bluetooth serial adapter.  It enables wireless connections to any legacy serial port and supports bi-directional RS232 or RS422 signalling at a rate of up to 464Kbps.  Just attach the FireFly to your device's RS232/EIA232/422 port, plug it in, and you're connected.  The transmit range can be up to 330' (100M), depending upon environmental factors.

There are several ways to utilize the FireFly serial adapter:

1. Direct to a Bluetooth client: The client creates a SPP connection to the unit and uses a virtual COM style interface.  Data is sent and received on the client exactly as if a serial cable was connected to a real COM port on the client.
2. Cable replacement: Utilized in cable replacement when pairing two FireFly with simple dip switches.
3. Access point mode: FireFly connects via Bluetooth into a BlueLine access point which can then be accessed from any client over the internet or LAN.  The FireFly serial port appears as a telnet port on BlueLine and network applications can open up a socket interface to the port.

Click here for the FireFly's technical specifications.

Click here for common questions and answers regarding the FireFly.

Features

• Very low power consumption (<10 mA discoverable, 40mA connected, 5mA sniff)
• Can be powered by a 9V battery that uses 40mA of power when connected and only 1mA of power in standby
• Bluetooth v2.0 compliant (also compatible with 1.2/1.1), FCC, IC, CE certified, RoHS
• Class 1 high power radio for long range operation
• Easy to use settings via on-board dip switches/li>
• Can be powered from pin 9 of serial port if available
• RS232 (RN-240M OR RN-240F) or RS422 (RN-422M) driver options
• CSR BlueCore04 chip/8Mb flash
• Secure and robust link, FHSS, 128 bit encryption, error correction, and guaranteed packet delivery
• High speed UART - RS232 interface
• UART baud rates from 1200 to 464K
• Supports SPP and DUN profiles
• Built-in stack/applications, auto-discovery, auto-connect, and instant cable modes
• 3 status LEDs
• 4 configuration dip switches
• Internal jumpers for DCE/DTE swap
• Dimensions: 24mm x 72mm x 15mm

Applications

• Wireless cable replacement
• Measurement/Monitoring systems
• Medical devices
  
• Asset tracking