Next project: 11/24. Does it need memory?

Chris Zach cz at
Sun Oct 18 22:59:41 CDT 2020

Weird. Set all the switches for the 11/24 CPU and Unibus map, and still 
nothing coming out of the serial port. Figured I would document the 
settings and see if anyone with an 11/24 can cross-check my settings.

Serial: Because my VT52 has a male RS232 end (factory) and the 11/24 has 
a male RS232 end (factory bulkhead) I am using a female-female null 
modem cable. This is the same cable I use on the 11/83 CPU and it's 
known working (along with the VT52). Is this the right type of cable to use?

Switches on the CPU are:

E135: off,off,off,on,off,off,off,on=9600 baud both signal generators.
E124: off,on,on,off (SLU1 use signal gen 1 for tx and rx)
E124 5-8: off,on,off,off (no idea what these are)

Slots in use are:
1--M7133 CPU
2--M7134 KT24 Memory map
3--M7891 MS11-L memory (configured for extended unibus), green light on, 
red light off
7-M7982 TS11 tape controller
8 M8256 RX02 controller
9 M9302 terminator and G7273 board

When powered on in HALT mode the 11/24 CPU board has the third LED on. 
Go to RUN stays on. Go to boot, LED goes off. If the unit is turned on 
with the switch in RUN, the light is out.

MS11-L has a green light on at all times. When I forgot the 9302 it had 
a red light on as well, but plugging that in and restarting cleared the 
red light on the memory.

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