[ale] Defining/ Redefining I/O port numbers and creating /dev/tty devices

[Mills.J at ems-t.com (Mills, John M.)]

ALErs -

I want to create some /dev/tty* using standard UARTs at non-standard I/O
addresses. I would expect there is some way to create such a special
file from a standard module and some invocation args describing the
hardware addresses and similar parameters.

How are these normally defined, and where could I look for background
and documentation?

TIA.
 - Mills