If you ahave questions on the PCF 8584 adapter for the EPP port, here are some comments from Johan Van Driessche, the wizard who designed it:
The I2C-adapter that I have developed uses the PCF8584 buscontroller from Philips, which is very good documented. It connects to any parallel port that supports EPP mode (IEEE 1284 compliant). The whole adapter fits into a 25 to 9 pins convertor housing and can be completely build in SMD.
The main advantages of the PCF8584 are that it supports almost every feature of I2C. The I2C-adapter can be connected directly to a (portable) PC. Furthermore, it improves the I2C-bus. Normally, you connect a pull-up resistor which gives you a logaritmic loading of the line capacity. However, if you load with a constant maximum current, you get a linear curve which improves the I2C-signal. This way, the maximum allowable line capacity of the I2C-bus is higher. Another benefit of this constant current source is that it reduces cross-over between SDA and SCL.