Re: USB-RS232 adapters vs. machines w/real consoles.

On Fri, 25 Nov 2016, John D. Baker wrote:

> I decided to investigate my various USB-RS232 adapters.
> 
> I have three Prolific pl2303-based adapters, one Belkin/MCT-based adapter
> and several KeySpan USA-19HS adapters.
[...]
> My only other experience with USB-RS232 adapters under penguin-OS is
> gNewSense 3 on my Lemote YeeLoong and it's a fairly bare-bones installation
> without a "desktop environment".  On it, the KeySpan works flawlessly.

Re-checking everything on the gNewSense/YeeLoong system, the Prolific
adapters and the KeySpan adapter work just fine.  They transmit BREAK
and otherwise perform properly.

The Belkin F5U109 (MCT--mct_u232) adapter also worked as a plain serial
port but did not transmit BREAK.  It has "Link", TX, and RX status LEDs.
I think the "Link" indicator is for USB traffic. When instructed to send
BREAK, the Link indicator blinked once.  Any other transmission/reception
flashed the TX/RX indicators accordingly.

Perhaps there was breakage of the MCT driver in NetBSD-7?  I last tried
it on an i386 system and it worked (long ago)--perhaps it doesn't like
amd64?  I'll have to arrange trying on other hosts with other versions
of the OS.


The Linux Mint system has so-far thwarted my attempts to operate any
USB-RS232 adapter without dbus and its minions interfering.  (I managed
to boot it single-user and start 'udevd', but 'cu' claims "Permission
denied" and that the port is in use, but it doesn't appear in 'lsof'
output.)

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