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.
*nod* -- Grant. . . . unix || die
