Although there are many options for IO and data communication with a Raspberry Pi, one older form that is lacking by default is an RS232 interface. This would be useful for communicating with older technology such as POTS modems, serial printers or even old video terminals.
However if this takes your an interest a tutorial published by Joonas Pihlajamaa describes a neat circuit based around the Maxim MAX3232 interface IC, with which some small external circuitry you can add the RS232 interface to your Pi.
So if you've seen an old VDU terminal or printer, perhaps have some fun and connect it to your Pi. To get started, visit Joonas' website. And for more, we're on facebook, Google+, and twitter - so follow us for news and product updates as well.
If you need to create your own RS232 interface, the external circuitry would fit nicely on our PiBreak board. It provides labelled breakout pins for all GPIOs, a large prototyping area with solder pads, and power rails for easy power connection:
Furthermore the PiBreak also includes mounting hardware to firmly attach it to your Raspberry Pi using a nut, bolt, and spacer - and is compatible with all revisions of both model A and B Raspberry Pi computers. For more information about our PiBreak board, our Getting Started guide, and to order - visit the product page.