First of all you will need a serial port. Some computers sold today no longer have them. If you do not have one you will need a USB to serial converter for use with it. Next you will need a terminal program to access the PK-232MBX. You may use Hyper terminal available in your Windows OS or download a free Logging program called Logger. It has a nice terminal in the program that is simple to program the many micros available for use with not only the PK-232MBX but also any other TNC. The link to download Logger is http://www.qsl.net/kc4elo/
You want to download the older Logger program and maby the upgrade to it. Do not bother downloading Logger 32 which is in Bata testing at this time does not have the terminal program yet installed and so you would be unhappy with it. While your at it you might also want to build a special interface box to use with the TNC. This interface is built with a DPDT switch to select eather the PK-232MBX TNC or with interface circuits made to connect to your computers sound card. You may download a PDF format file on building this interface at http://www.geocities.com/n4zou/files/tnc-psk.pdf
this will allow you to use sound card programs for modes like PSK-31 and modes like ARQ Amtor and ARQ mode Pactor available only on a TNC like the PK-232MBX.