Hello all, I have an old memory patch panel, probably a diode matrix. Estimated to be from the early 60's, maybe IBM? Pictures are at http://i36.tinypic.com/29paqfb.jpg http://i37.tinypic.com/2h6tzd5.jpg http://i34.tinypic.com/51wl6h.jpg I have 3 kinds of diode plugs that fit in the sockets It has white plugs with one type of diode in it. It has brown plugs with a different type of diode in it It has grey plugs that will be a short. So it appears that each location can have one of four values open, short, diode1 or diode2. I am interested to find out more about this - any information such as documentation, model, or what it belonged to would be helpful. Thanks! Bob Roswell broswell at syssrc.com Bob Roswell System Source broswell at syssrc.com (410) 771-5544 ext 4336