Omnibus Memory Extension and Timeshare Option
<UL>
<LI><b>M837</b> is a drawing of DEC's M837 Omnibus Timeshare Option board,
which uses a lot of hard to find chips.
<LI><b>M837bb</b> is a version of M837 with the signals renamed to match their function.
<LI><b>M837cc</b> is a variant without the the TP_CB1 input.
</LI>