VT340 Emulation

Grant Taylor cctalk at gtaylor.tnetconsulting.net
Thu Jun 24 19:51:26 CDT 2021

On 6/22/21 9:12 AM, Ethan Dicks via cctalk wrote:
> The OP said he meant with "real" connectors, but in my case, 
> I've encountered strange buffering issues with USB serial dongles 
> (since they are really block-mode devices, not character-at-a-time) 
> and I've definitely had problems supporting lines with odd parameters 
> (especially speeds slower than 300 baud or with 5-bits-per-char, like 
> one would use for a Model 19 or Model 28 teletype).  The hardware UARTs 
> on AVR processors implement those juse fine (though for "50 baud", 
> you often have to put a slower crystal on the processor because the 
> 16-bit divisor overflows at 16-20MHz).  The "soft serial" libraries 
> often just hard-code 8-bit implementations.  Fine for modern stuff 
> but I have uses for connecting to electromechanical serial devices.

These seem like real problems, which can't be overcome by a passive 
physical adapter.

These also seem like implementation problems to me.  At least more than 
they seem like a USB spec problem.  I naively assume that if someone 
wanted to produce a USB-to-Serial adapter that supported the things 
you're describing that they could do so.  But sadly, I believe that RoI 
will be on the wrong side of the demand curve.

> In terms of a CRT terminal, though, most modern serial implementations 
> are fine.


Grant. . . .
unix || die

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