Connecting to a USB serial port

[perryh at pluto.rain.com]

> I have a Keyspan USB serial port on my FreeBSD 6.1 box and trying
> to connect from a Linux box to the machine. I'm using minicom and
> not sure of the settings that should be used. I see the following
> in dmesg...
>
> sio0: <16550A-compatible COM port> port 0x3f8-0x3ff irq 4
> flags 0x10 on acpi0
> sio0: type 16550A
>
> Is this the USB serial port? There is no other serial port avaialble
> on the server, but could be something in the board, not sure.

I doubt it.  That looks like a normal board-resident serial port,
esp. with the "on acpi0" notation (which suggests that it is part
of an ACPI-controlled device, and ACPI is ordinarily aware of only
motherboard devices).  It's likely part of the "super-io" chip,
and it may possibly be connected to a 10-pin Berg header on the
motherboard (or it may not be connected to the outside world at
all).  The motherboard manual, if available, might provide a clue.