external Links
DEC Backplanes: http://web.frainresearch.org:8080/projects/pdp-11/backplanes.php
DEC Field Guide: ftp://ftp.update.uu.se/pub/pdp11/doc/pdp11-field-guide.txt local copy: pdp11-field-guide
M9312 Boot Prom Images and Details: https://www.ak6dn.com/PDP-11/M9312/