Andy Ball wrote:

> I have a USB->RS232 adaptor that shows up in dmesg output...
> 
>     uplcom0 at uhub0 port 1
>     uplcom0: Prolific Technology PL2303 Serial adapter
>     (ATEN/IOGEAR UC232A), rev 1.1 0/2.02, addr 2
>     ucom0 at uplcom0

We have a bunch of both the ATEN/IOGEAR and the ATEN/Tripp-Lite
units. These are brownish translucent units which appear to have
the identical components inside and respond with only a different
manufacturer id.

We use the Tripp-Lite units on OS/X with the Prolific driver where
we added the Tripp-Lite manufacturer id to the driver packages'
xml Info.plist. (The IOGEAR units claim to support OS/X whereas
the Tripp-lite doesn't claim such but works with just the plist
change). The IOGEAR units worked on OS/X with the Prolific driver
as delivered, so I suspect they are all the same units internally.

uplcom0 at uhub1 port 2
uplcom0: ATEN International Serial adapter, rev 1.10/0.01, addr 2
ucom0 at uplcom0

uplcom0 at uhub1 port 2
uplcom0: Tripp-Lite U209 Serial adapter, rev 1.10/0.01, addr 2
ucom0 at uplcom0

>     ...but when I try to connect throught it, I get an error
> message...

If it got as far as 'ucom0 at uplcom0', it appears to be using
known manufacturer and model ids, so I would think the device should
be ready to go at this point.

>     $ cu -l /dev/dtyU0
>     cu: Can't set terminal settings: Input/output error

I can't manage to get this error. What version of NetBSD are you
trying this with?

> ...does this look familiar to anyone? Does it just mean that
> my adaptor is not supported?  It's translucent blue plastic,
> with no evident brand name (it has "CP-US-03", which I'm
> guessing is a model number).

http://extremetech.shopping.com/xPO-Splitters_CP_Tech_CP_US_03_USB_to_Serial_Adapter
CP Tech - CP-US-03 - USB to Serial Adapter
has a very slightly different housing than the IOGEAR or Tripp-lite units.