"RS232 is meant for simple easy communication in friendly conditions. "

That, is a revelation of sorts. Maybe by friendly you mean short distances, noise free environment etc...

"to attach a modem that lies on a shelf to a PC under your desk."

What will happen if the modem lies OVER the desk ;-)

Whenever you are posting a "detailed" reply it would be better if you take care to check on, atleast the basics. Most of what you wrote "generally" convey that RS485 is for serious applications and RS232 is for friendly folks who would'nt mind loosing a "bit" here and there.

Sorry if I sound harsh - just a friendly nudge. Nothing more to it ;-)

Raghu