nikhil_s said:
1. Do we need MAX232 Line drivers and a microcontroller (for what function) to interface between the PC and the RF module? (I am acquainted with programming of the 8051)
You need to convert from the +/-12V signal levels of RS232 to a logic level, a MAX232 is a common way of doing so - although there are many others, some of which are far simpler and cheaper.
A uP is a good idea, as it allows you to go the required coding and encoding - the usual method used is Manchester coding.
2. Does circuit complexity increase drastically if we implement in Full Duplex? (Currently considering MT8870D or MT8888C)
Yes, to some extent, for full duplex you require two transceivers on different frequencies (usually on different bands), so one can transmit while another receives.
3. How would one go about doing the PCB layout...does anyone have relevant schematics with layouts and circuit details?
Check the datasheets for the manufacturer of the RF modules, you will also find that such RS232 RF modules are available ready built - and you might find it useful to study their specs?.