I was thinking about this the other night {it was a slow night :-)} -- how does the DC option on the PDP-11 work (besides the obvious)? My 11/34 has a DC light on the panel, but I know that my unit did not come with a battery backup unit. What was involved with the DC option? Was it a special PSU and batteries? Or was it a board and separate UPS? Just curious... Rich Cini/WUGNET &lt;nospam_rcini(a)msn.com&gt; - ClubWin/CW7 - MCP Windows 95/Windows Networking - Preserver of "classic" computers <<<< ========== reply separator ========== >>>>>