[vcf-midatlantic] portable terminal preferences

Herb Johnson hjohnson at retrotechnology.info
Sun Jan 3 23:57:10 UTC 2021

> I'm curious what everyone else uses to connect to their various machines.
> Straw poll? Thoughts?

1) use a device with a REAL RS-232 UART. Not a USB/serial dongle.


Here's a somewhat busy note about using a FTDI-brand TTL-to-USB dongle, 
on a 8-bit microcomputer to a USB based modern computer. It references 
some other information too. But the problem I want to call out in 
general, is the "layers of character flow control" section of the document.

The problem in brief, is that a USB serial dongle has its own buffers 
and hardware and software handshaking. It is a microcontroller after 
all. It's only vaguely controlled by the modern computer with the USB 
driver, which may or may not have user-means to operate. Most people use 
these dongles with old "terminal emulators" that think THEY have a 
buffer and some handshaking control of a UART. The USB driver arbitrates 
some of that, but not always well.

It's all too busy, and generally means a slower sustained baud rate to 
avoid loss of characters. And for long runs of characters (like XMODEM) 
you get losses anyway. I think trying to run an 8-bit micro at 19.2K 
baud at length, is asking for trouble. But people get obsessed about 
high baud-rates. And certainly it's no fun, to transfer a file and find 
errors, even with XMODEM and other protocols.

So - find a computer with a real, live, UART buried in it. They still 
exist. And in fact, that GPD MicroPC suggested, *has* (apparently) a 
RS-232 port. Too fancy for me, any 1990's laptop will do. Some of them 
still work well. Even some post 2000 laptops and desktops have serial 
ports. Use those, available from any industrial dumpster.

Regards, Herb Johnson

Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net
preserve, recover, restore 1970's computing
email: hjohnson AT retrotechnology DOT com
or try later herbjohnson AT comcast DOT net

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