"Ersatz-11" PDP-11 console
running Ersatz-11/35 front

With the description in the demo version of Ersatz-11 from John Wilson you can connect a simple LED display to the parallel port of any PC. The 16 LEDs show the datapath of the PDP-11 that you are simulating with Ersatz-11. To get the LEDs active enter the following statements in the E11.ini file or just enter them on the command prompt.

SET LPT2: PORT=0278 NOBIOS NOIRQ
SET DISPLAY LPT2:
SET DISPLAY R0

Of course, you must specify the correct output port. On my 486 running Ersatz-11 the LEDs are connected to an extra ISA card providing LPT3 on the rear via a DB25 connector and an LPT2 port internally via a BERG connector. When you run your simulated PDP-11 in Ersatz-11 the LEDs will display the patterns you are used to from a real PDP-11 that has a true full panel.
To see the LEDs change while in E11-prompt mode using the command DEPOSIT 777570 xxxxxx, use SET DISPLAY DR.
RT-11 uses R0 to output to 777570.

If your PC runs RedHat Linux, and you want a nostalgic feeling, build the simple 16 LEDs hardware and connect that to the parallel port. With the following small program the LEDs produce a "blinkenlight" (random) display. Enjoy!

blinkenlight program C source code (3 kBytes)

To connect a PC, that runs Ersatz-11, to control more than just the 16 DATA LEDs, you need extra:

hardware to display the address bus and the status information on LEDs
hardware to read in the address/data switches
hardware to read in special switches (e.g. HALT/ENABLE) , toggle switches (e.g. EXAM, DEP)
and the display knobs found on the 11/45 - 11/70 consoles
software support in Ersatz-11

All the extra hardware must be able to communicate with the Ersatz-11 software. E11 must tell the hardware which LEDs must be on and off, and the hardware part must tell E11 the switch information so that E11 can react corresponding the real console.
The communication between E11 and the extra hardware must run over a serial link since serial I/O is supported in the demo version of E11 (parallel I/O is only supported in the commercial version).

To make this console work it is obvious that the support of John Wilson is needed.
I have had some contacts with John, and he is interested in the project.
As for us all, time is a very valuable resource ...