So an update to my previous "Altair can't jump" thread - turns out it was something on that serial board, as I was finally able to get a 88-2SIOJP from Martin Eberhard, and it works great and the Altair CPU had no problems whatsoever running CPM, Basic, and a variety of other software I threw at it. I'm amazed at how awesome these reproduction boards are for these things (my Altair had ONLY a cpu board in it). I do plan to revisit that card though as I can now use the monitor on the 2SIO to test/troubleshoot it much faster than toggling 60+ bytes every time. Next question - I went to mount the DB25 serial ports into the back of the cabinet, to find that the panel is pretty thick, and really prevents the plugs from connecting properly with the locking screws (screwnuts?) in place. (I'm coining that word!) It also seems like the nut part of the screw would have to be half as deep to compensate for the thickness of the panel. I can grind it down but then it'd only leave a couple threads left. I think I can overcome this using the serial cables included with the 2sio card by actually mounting them on the outside surface, if I can find some longer screwnuts that would go all the way through the housing and the panel. Something like this but maybe a hair longer: https://www.aliexpress.com/i/32997261872.html Anyone else have any other ideas though? I'm good with IDC connectors and ribbon cable so could always use a different connector. I think i've seen some older uber-deep DB25s and now I know why they existed lol. Jeff aka Bags