On 04/23/2013 10:15 AM, Mouse wrote:
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.
you need the bulkhead adaptor to set baud and all.
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.
[...]; if I
look at the docs, it looks like it should be fine
assuming I can let DTR float (it's unused in my cable, since it's an
external clock pin on the KDF11-B).
If you get any output, I would assume, until
finding evidence
otherwise, that DTR is not an issue.
If you can quote some of the garbage you get (preferably a hex dump of
the serial-line data, since there may be nonprintable characters in
it), we might be able to make guesses from that. In particular, "wrong
speed" garbage usually has a very different feel from other kinds of
garbage, but in a way I, at least, find difficult to elucidate.
You will have to
make your own cable, that fakes the bulkhead switches.
Allison
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