Linx have no example codes for MCU application when sending serial data. I connected one RF module directly to an 8052 UART, and send some characters. The receiver was connected to a pc ( dump terminal ) RS232, about 500 meters away. The distance of the modules was 1KM at 900Mhz. I find that there is rubbish & characters recieved by PC.....so since I'm a dumb guy, I'll have to search the web to see if i can get some sample code to play with or a chip that might resolve the problem....this is as you guys have suggested. But plz, don't stop....if you can help this dummy.