Re: Couple of ZX81 Interfaces / Boards
Posted: Tue Jun 09, 2015 1:19 am
Optrek-RS stands for Pull-up Resistance(s) The book was originally written by Stephen Adams (1982), but this board comes out of the dutch version Published by Kluwer (mine has ISBN 90201 1640 1 that was the 3rd print 1984)