Hi,
I’m new to FEZ and I wanted to know if it was possible to have an RS232 I/O and an Ethernet I/O together on a single FEZ board?
The device will act as a filter/converter for the communication between an Internet based application (Ethernet I/O) and another hardware device (RS232 I/O).
A general question is, is it possible to connect multiple shields to a single FEZ board? what are the limitations?
Thank you in advance.
Yes, the Ethernet shield use SPI pins where RS232 uses UART0 (COM1). They work together just fine.
There is no straightforward way to know if shield work together. You need to check schematics to know…an easier way is to just come here and ask 
That is why we are here 
the challenge is knowing what shields use what pins, and what pins are “shareable” and what are not. That is why it’s not a simple answer to the general limitations.
For instance, two SPI-based shields CAN be used together, as long as the CS pin is different; but if they use the same CS pin, then one needs to be modded (bend the pin plus jumper a new CS to an unused pin).
The Shield List is a new great resource for Fez shield info since a lot of them are re-used from the Arduino crowd. Check out [url]Arduino Shield List: Unknown Unknown and take a look.
These are good news 
Many thanks for the quick and helpful replies.