Lpc2000

Dear ARMiesssss.........

I am very new to ARM world ,I am interfacing serial port with lpc2214
that is db9 connector and want to programme my lpc2214 with the same
as well as I want to interface an external modem so can I use same
serial port for both the purpose??

What should be the ideal crystal frequency which could be best for my
case.

for serial communication I read UART part from the manual and GPIO
part what else I need to study for that? GUIDE ME PLEASE

PLEASE HELP

Pankaj