Yes and no. There are separate manuals for the EAE (links here: https://gunkies.org/wiki/KE11-A_Extended_Arithmetic_Element https://gunkies.org/wiki/KE11-B_Extended_Arithmetic_Element the -B is the same to program as the -A; its implementation is just a single board, though) but the -11/20 processor handbook (the second version; the one dated 1972) does have a chapter (Chapter 8; Part I) on the EAE. (For no reason I can understand, neither the -11/05 nor the -11/04 processor handbook covers the EAE, even though neither one has the EIS, and if you need multiply/etc in hardware on either one, the EAE is your only choice). Noel