[gentoo-user] Re: Serial port over ethernet

[Grant Edwards]

On 2008-07-16, Zdenek Travnicek <v154c1@×××××.com> wrote:

> I would like to connect serial port from remote machine to my
> laptop and use it for PIC programmer. (both machines are
> running gentoo) It's easy to tunnel data using nc or similar
> tool, but it won't give me ioctl access to the port itself.
> (Or did I miss something?) Is there any tool/project that
> exports the whole device and make virtual one on the local
> side?

The implimentations that I've seen for remote serial ports use
a pty on the "master" end.  On Linux (and AFAIK BSD), ptys only
support a small subset of the features of a real serial port.
If you need to do things like set parity, set the number of
stop bits, set the character length, or interface to modem
status/control lines you're out of luck.

> I searched google for quite a while but without any success.
> There are many standalone devices for rs232->ethernet->rs232,
> but I don't want a standalone device...
>
> I realize it will be slow, but I dont care for lower speeds.

Speed isn't the problem.  The problem is the Linux pty driver.
To impliment a working remote serial port, you have to write a
kernel-mode serial driver -- and that's a lot of work. [Writing
one isn't bad, maintaining one is a complete bitch due to the
way the infrastructure keeps shifting out from under you.] I've
proposed fixing the pty driver to allow it to emulate a real
serial port, but that proposal wasn't well accepted by the
powers-that-be in the Linux kernel world.

-- 
Grant Edwards                   grante             Yow! PUNK ROCK!!  DISCO
                                  at               DUCK!!  BIRTH CONTROL!!
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