"Digital serial yes, but it will not be RS-232."

Absolutely!
If all you want is an asynchronous serial link, then that'll be fine; but it will not, as Erik says, be RS-232!

RS-232 specifically requires that the signal swings both above and below 0V.
If it doesn't do that, then it is not RS-232!

There are also various other requirements, too - for full details of the official, formal specification of RS-232, look here:
http://www.8052.com/forum/read.phtml?id=24916