I'm having a RF module 433Mhz having a maximum data transfer rate of 4.8kb/sec. Can I use in UART mode if so what baud rate should I use?
Thanks in advance..

 

You cannot simply connect the TX of your 8051 to the Din of your RF transmitter module. Do a simple experiment. Send a continuous clock to your RF tx module and you will be able to receive the same clock at the RF rx module. However, if you send a continuous logic "1", you will not get a continuous "1" at the RF rx.