http://margo.student.utwente.nl/el/
pc/ad_da

4chan8bi  .zip      4 channel 8 bits AD port for printer port, including hard- and software.
adda10    .zip      AD and DA converter on printerport.
covox     .zip      Contains Microsoft Windows sound drivers for parallel port DAC circuits.
covox1    .zip      Covox circuit.
covox2    .zip      Another covox circuit.
covox3    .zip      Another covox circuit.
digitize  .zip      Play voices on PC speaker.
lpt-adc   .htm      8-bit ZN448E-based ADC to interface to a PC parallel port.