23 Apr
2013
23 Apr
'13
9:26 a.m.
On Apr 23, 2013, at 11:26 AM, Allison <ajp166 at verizon.net> wrote:
It's a weird hybrid, in that there is a differential receiver. But
if you ground one leg of the receiver, it's fine. I'm using the same
cables that I use on my -11, and that works fine.
As I mentioned in an update, it turns out that I had plugged the cable
in upside down because it wasn't keyed either mechanically or visually.
On 04/23/2013 10:15 AM, Mouse wrote:
you need the bulkhead adaptor to set baud and all.
Or jumpers, but yes. If the switch pins are all open, that does
correspond to 300 baud, as expected.
I
recently acquired a KA655-AA (MicroVAX 3800/3900 CPU) and some
appropriate RAM, and I'm having trouble grokking the console SLU
output. [...] if I'm running it without a bulkhead attached at all,
the serial speed should be 300 baud. When my terminal is running at
300, 8 bit, no parity, 1 stop bit, I get some garbage on screen but
not much more.
Have you tried the other speeds the KA630 documentation mentions?
It
strikes me as possible, at least, that the KA630 interprets those
signals differently from the KA655. The other
possibility that comes to mind is that its serial output
isn't a normal single-ended RS232, but a differential pair (my memory
calls that RS432, but I don't know how accurate that is) and you've got
the wrong output pin - inverting the data line produces weeeeird data
corruption. (I know because I once made that mistake myself and was
thoroughly baffled for quite a while until I realized what was up.)
Its RS423. Its an abbreviate flavor of RS232 for fewer active pins. You will have to make your own cable, that fakes the
bulkhead switches.
It's working for now, but I definitely have plans to make a small board
to do that; among other things, the bulkhead also supplies the battery
power for the NVRAM and switches for run mode, etc. that I need. I
just haven't had time yet.
- Dave