TU58 problems

Brian L. Stuart blstuart at bellsouth.net
Sat Jan 16 17:00:31 CST 2016

On Sat, 1/16/16, tony duell <ard at p850ug1.demon.co.uk> wrote:
> I tried a RS232 analyser between the TU58 and the VAX. Very odd. Either
> my RS232 anaylser drops 00 bytes or the TU58 sets short result packets. The
> meaningful bytes (response code, etc) are there, but things like the sequence
> number are not. Odd...
> Does anyone have any sensible ideas as to what to try next.  At the moment
> I have no idea if it's the tape, heads, roller or what....

If it were me, I'd start by setting up some tests to determine what exactly
the protocol analyzer is doing.  If it really is dropping 0 bytes, then I'd
probably hack up a home grown capture using a couple of serial ports.
If the controller and the VAX really are speaking the right protocol to
each other, then it's time to worry about the correctness of the data.  On
the other hand, if the controller really is not sending all the bytes it should,
I'd check for bit rot in the EPROM.


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