Keil has some knowledge base information on using the 8051 UART in C51 at their web site. Here is a link to one sample.

http://www.keil.com/support/docs/685.htm

In this sample the code looks like:



The immediate thing I see is that a small bit more initialization is included beyond what you have in your program. Why don't you try something like this example without printf() first. You can in a first pass even eliminitate the input key fetch and just spew out a whole bunch of 'A' and 'Z' characters.

Michael Karas