Linux

If you have a graphical Bluetooth manager, you can use that to pair your computer to the Bluetooth module and skip most of these steps. You'll probably still have to this step though.

Power up

First, your computer's Bluetooth transceiver may be OFF. Check its status with hciconfig and turn it ON if necessary:

$ hciconfig
hci0:   Type: Primary  Bus: USB
        BD Address: 68:17:29:XX:XX:XX  ACL MTU: 310:10  SCO MTU: 64:8
        DOWN  <--
        RX bytes:580 acl:0 sco:0 events:31 errors:0
        TX bytes:368 acl:0 sco:0 commands:30 errors:0

$ sudo hciconfig hci0 up

$ hciconfig
hci0:   Type: Primary  Bus: USB
        BD Address: 68:17:29:XX:XX:XX  ACL MTU: 310:10  SCO MTU: 64:8
        UP RUNNING  <--
        RX bytes:1190 acl:0 sco:0 events:67 errors:0
        TX bytes:1072 acl:0 sco:0 commands:66 errors:0

Then you need to launch the BlueZ (Bluetooth) daemon:

• On systemd based Linux distributions, use:

$ sudo systemctl start bluetooth

• On Ubuntu (or upstart based Linux distributions), use:

$ sudo /etc/init.d/bluetooth start

You may also need to unblock your Bluetooth, depending on what rfkill list says:

$ rfkill list
9: hci0: Bluetooth
        Soft blocked: yes # <--
        Hard blocked: no

$ sudo rfkill unblock bluetooth

$ rfkill list
9: hci0: Bluetooth
        Soft blocked: no  # <--
        Hard blocked: no

Scan

$ hcitool scan
Scanning ...
        20:16:05:XX:XX:XX       Ferris
$ #                             ^^^^^^

Pair

$ bluetoothctl
[bluetooth]# scan on
[bluetooth]# agent on
[bluetooth]# pair 20:16:05:XX:XX:XX
Attempting to pair with 20:16:05:XX:XX:XX
[CHG] Device 20:16:05:XX:XX:XX Connected: yes
Request PIN code
[agent] Enter PIN code: 1234

rfcomm device

We'll create a device file for our Bluetooth module in /dev. Then we'll be able to use it just like we used /dev/ttyUSB0.

$ sudo rfcomm bind 0 20:16:05:XX:XX:XX

Because we used 0 as an argument to bind, /dev/rfcomm0 will be the device file assigned to our Bluetooth module.

You can release (destroy) the device file at any time with the following command:

$ # Don't actually run this command right now!
$ sudo rfcomm release 0