Schmitt Trigger, +/-10V in, 0 and -3V out
<UL>
<LI><b>W501D</b> is a drawing of DEC's W501D.</LI>
<LI><b>W501F</b> is a drawing of DEC's W501F.</LI>
<LI><b>W501X</b> is a 'modernized' W501.</LI>