On Mon, 14 Sep 1998, Tony Duell wrote: I found the perfect book to answer this question over the weekend. Its called _The Apple II Circuit Description_ by Winston D. Gayler. It includes in-depth technical descriptions of the Apple II and detailed fold-out schematics of every major subsystem in the Apple II, including the CPU, the bus pinouts, the keyboard, etc. This should answer your question: "Quad-mode operation--B6 is a quad-mode encoder. This means each key can generate up to four different characters as a function of the SHIFT and CTRL keys. "Lowercase--there are two bow ties on the board with the ICs [the encoder board]. They may be cut as a user option. The circuit is then restored by adding switch S2. In the normal position of S2, the circuit functions as previously described [ie. normal Apple II keyboard encoding]. When S2 is operated, output bits 9 and 8 are substituted for bits 5 and 6. Encoder B6 has been programmed with ASCII lowercase letters. This substitution of bits will make the lowercase letters available. Lowercase operation is as follows: with the shift key not depressed, pressing any letter key will output lowercase. With the shift key pressed, pressing any letter key will output uppercase. Numeric pad--As a user option, a nine-pin connector may be installed on the keyboard at J2. Then J2 can be extended to a numeric pad." Let me know if you have any more specific questions. This book is excellent. Sam Alternate e-mail: dastar(a)siconic.com ------------------------------------------------------------------------------- Ever onward. September 26 & 27...Vintage Computer Festival 2.0 See http://www.siconic.com/vcf for details! [Last web site update: 09/12/98]