Arduino is the name of the hardware board and of the software IDE needed to program the board. You can interface them at two levels: hardware and software.
Interfacing - hardware:
If you want to learn how to connect various components, shields, bluetooth antennas and other hardware devices to the Arduino board please look under:
Interfacing - software:
If you want to learn how to let the Arduino board "talk" to different software you are in the right place. Arduino "talks", transmits data in Serial format, so any other program/programming language that has serial capabilities can easily communicate with Arduino. Some programs (like Flash) don't natively speak Serial but they can still communicate with Arduino through an intermediary, that like a translator enables them to talk to each other. Read through the specific sections and you will find references on how to interface Arduino with every possible software that has been connected so far.
placeholder for something coming soon
the Arduino basic code
further info: rs232 standard + parity explanation ecc
- interfacing arduino as a Linux TTY (?)