VAX4000 VLC diagnostics/console

Antonio Carlini a.carlini at
Thu Jul 15 02:03:35 CDT 2021

On 14/07/2021 18:32, Adrian Graham via cctalk wrote:
> VT100 to the rescue, the VLC is fine talking to it so now I'm wondering why
> my old faithful hardware UART in this PC I'm typing on now has let me down.

Given the possible issues (dead VLC line drivers, iffy cable, iffy PC 
UART) you've probably bee lucky (although maybe DECconnect cables aren't 
too tricky to make up these days).

Funnily enough I have a very similar issue on my MicroVAX 3600: the CPU 
bulkhead LED cycles through the right stuff but nothing appears on the 
VT420. Take the lead out of the uV3600 and plug it in to the VS400-60 
and it's fine. The leaky battery on the console bulkhead probably didn't 
help :-( At least you don't have *that* issue on the VLC!

It would be nice to know if Bluepill works on the VS4000 range: I wonder 
if my VS4000-90 would then become silent enough to run more often!


Antonio Carlini
antonio at

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