We tested different external Bluetooth dongles; with the following, we could successfully pair PocketScan:
Hama Bluetooth USB Adapter Class 2
Hama Bluetooth USB Adapter Version 2.1
Hama Bluetooth USB Adapter Version 4.0+EDR
Promate BLUEMATE.3 bluetooth dongle
Promate BLUEMATE.4 bluetooth adapter
Canyon CNR-BTU6 Dongle Class 2
If your Bluetooth dongle is not listed, it is of course still possible that it works. However, if you need to purchase one, we suggest to purchase one of the above.