How to create a virtual serial port?

[Scott David Daniels]

Grant Edwards wrote:
> On 2009-04-11, Grant Edwards <grante at visi.com> wrote:
> 
>> You can write a port redirector in user-space in MS-Windows,
>> but you can't in Linux/Unix.  On Unix systems you have to
>> write a kernel module that sits below the tty layer.
> 
> Perhaps I should elucidate further.

This part I actually understand.  The OP has a program named
"RouteBuddy" that talks to a device over a serial port, and he
want to repalce the data stream coming from that device.  My
question is, "where does the device that he wants to replace
plug in?"  I don't see anywhere on my laptop I could plug in
anything but a USB connector, an ethernet connector, a firewire
connector, headphones, speakers, a display connector, or a
power cord.

--Scott David Daniels
Scott.Daniels at Acm.Org