6 Sets of 2-Input ANDs ORed, both polarities out, PDP7
<UL>
<LI><b>B171B</b> is a drawing of DEC's B171B.</LI>
<LI><b>B171C</b> is a drawing of DEC's B171C.</LI>
<LI><b>B171X</b> is a 'modernized' B171.</LI>