On Sun, Aug 2, 2026 at 8:44 PM Jon Elson via cctalk <[email protected]> wrote: > The ground was the problem. For some CRAZY reason, pin 5 of > the 9-pin serial connector of the KA630-AA and cabinet kit > has a 1K Ohm resistance to system ground.
I don't doubt that you had a problem with ground, but on a MicroVAX console port, Pin 5 is not ground. Ground is Pin 7. There are pinout similarities with a PC DE9 serial port, but AFAIK it's not intentional. 1: Protective Ground 2: Transmited Data 3: Received Data 4: Request To Send (RTS) 5: Data Terminal Ready (DTR) 6: Data Set Ready (DSR) 7: Signal Ground 8: Shorted to pin 9 on MicroVAX and VAXstation 2000... 9: ...series systems, otherwise left floating. BCC08 cable has 8-9 shorted because it was the standard console cable back when "real" serial ports were on DB25s. I forget which machines actually use it to detect if a serial console is attached. -ethan
