I'd do prep and all the heavy lifting with a PC that has a real serial
terminal, get it working correctly, and then tackle the USB2Serial issues.
Not all adapters work correctly and they are a headache to rely on.
b
On Wed, Jul 15, 2026 at 12:23 PM Brent Hilpert via cctalk <
cctalk(a)classiccmp.org> wrote:
On 2026Jul 15,, at 8:26 AM, Jon Elson via cctalk
<cctalk(a)classiccmp.org>
wrote:
I am trying to get my old VMS system going for demo at VCFMW.
I got a USB-serial adapter, and it mostly works OK. I am using minicom,
and trying to get the Emulex firmware resident diagnostics loaded on the
uVAX. This requires entering a BUNCH of ODT commands. I tried to put
these in a file, and then do an ASCII send file command in minicom, but it
gets garbled. I assumed that minicom was sending too fast, so put in a
bunch of delays on each character and on linefeed. I did this in the T
(terminal) menu. I can clearly see these delays work when typing on the
keyboard, but they DON'T seem to work when sending the file, as the file
send doesn't take any longer to complete. Is there another place to set
delays that is effective for ASCII send?
Also, minicom doesn't seem to save these terminal (T) settings when
restarted.
Should I be using a different program?
This sounds like the inherent problem with USB-serial adapters.
The terminal program (minicom in your case) may well be adding the
per-character delay, but somewhere in the host-to-USB stream the characters
are accumulated in a buffer/packet, when the USB adapter finally gets them
it sends them out to its serial port all at the regular bps rate, sans the
inter-character delay.
Or at least, I have had such a flow control problem in trying to emulate a
paper-tape reader (for downloading BASIC programs to an HP2116). Adding
delays, adding TC_FLUSHES to the terminal program, etc., were of no effect.
In that situation, I was eventually able to resolve it by adding some code
to (my) terminal program to wait for the LF returned by the receiving
software (BASIC interpreter on the 2116) after sending the EOL CR, that is,
using the LF as an ACK.
If it might work for your situation, or if you want a hackable terminal
program:
http://madrona.ca/e/scomm/index.html