Tried out to connect HC-06 Wireless Bluetooth Transceiver to Arduino Pro Mini. The resulting code to blink the on-board led via BT serial is the outcome.
At the same time I've tried fritzing.org to draw breadboard, schematics and PCB.
After Bluetooth pairing (pin 1234) /dev/rfcomm0 becomes available.
`minicom --device /dev/rfcomm0`
Here the source code: