Hi,
first: I don´t know if there is a site for this...
but if there is one, i doubt it is helpful for beginners.
It depends on so much parameters, so that there is a huge ammount on information....
UART - a simple interface on the one side, but a lot of details on the other side.
* baudrate
* protocol
* hardware (RS232, RS485, RS88, optical fiber, IRDA....)
* half duplex, full duplex
* control lines
* echoing
* addressing
* and a lot of other things
**********
I recommend to first look for the application, transmitter, receiver and their datasheets.
Klaus