Adding TCP/IP Ethernet to PIC - how?

[dhouston]

1.- Assuming I connect a well-configured ConnectOne NANO LANReach module to a network (office or so), is it going to be "pingable" just like if I ping another PC?

Yes - but only if you've written PIC code to respond to a ping.

2.- What is different between the possible protocols the module supports? Is it only the way the data is organized in the packet?

This is is too big a topic to discuss meaningfully here. Try...http://en.wikipedia.org/wiki/Internet_Protocol

3.- Is there a difference if the module is directly connected to a PC or the module is connected to a network (i.e. via a switch)?

No, except you will probably need a cross-over cable for the direct PC connection.

4.- What makes a module's address unique? The IP address and the port? Or is it the MAC address?

The MAC address is usually fixed and unique. the IP address is changeable.

That's enough for now

Good - I'm tapped out. Maybe mackrackit can elaborate on my answers.